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Information And Knowledge Systems 1st Edition Pierreemmanuel Arduin
Information And Knowledge Systems 1st Edition Pierreemmanuel Arduin
Information And Knowledge Systems 1st Edition Pierreemmanuel Arduin
Information and Knowledge System
Information And Knowledge Systems 1st Edition Pierreemmanuel Arduin
Advances in Information Systems Set
coordinated by
Camille Rosenthal-Sabroux
Volume 2
Information and
Knowledge System
Pierre-Emmanuel Arduin
Michel Grundstein
Camille Rosenthal-Sabroux
First published 2015 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc.
Apart from any fair dealing for the purposes of research or private study, or criticism or review, as
permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced,
stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers,
or in the case of reprographic reproduction in accordance with the terms and licenses issued by the
CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the
undermentioned address:
ISTE Ltd John Wiley & Sons, Inc.
27-37 St George’s Road 111 River Street
London SW19 4EU Hoboken, NJ 07030
UK USA
www.iste.co.uk www.wiley.com
© ISTE Ltd 2015
The rights of Pierre-Emmanuel Arduin, Michel Grundstein and Camille Rosenthal-Sabroux to be
identified as the author of this work have been asserted by them in accordance with the Copyright,
Designs and Patents Act 1988.
Library of Congress Control Number: 2015940032
British Library Cataloguing-in-Publication Data
A CIP record for this book is available from the British Library
ISBN 978-1-84821-752-2
Contents
PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi
CHAPTER 1. INFORMATION SYSTEMS AND DIGITAL TECHNOLOGY . . . . . . 1
1.1. The concept of information systems . . . . . . . . . . . . . . . . . . . . . 1
1.2. History of the concept of information systems . . . . . . . . . . . . . . . 5
1.2.1. The centralized processing stage (1950s–1960s) . . . . . . . . . . 5
1.2.2. The data decentralization stage (1970s–1990s) . . . . . . . . . . . 6
1.2.3. The interoperability and standardization stage (1990s) . . . . . . . 6
1.2.4. The universality and globalization stage (2000 onward) . . . . . . 7
1.3. What is “digital” technology? . . . . . . . . . . . . . . . . . . . . . . . . 9
1.4. Information systems and digital technology for business . . . . . . . . . 11
1.5. Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
CHAPTER 2. KNOWLEDGE MANAGEMENT. . . . . . . . . . . . . . . . . . . . . . 17
2.1. Historical overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
2.2. Knowledge Management: two dominant approaches . . . . . . . . . . . 20
2.2.1. The technological approach. . . . . . . . . . . . . . . . . . . . . . . . 21
2.2.2. The managerial and sociotechnical approach to KM . . . . . . . . . 22
2.3. Specific management principles for KM. . . . . . . . . . . . . . . . . . . 23
2.3.1. Definition of Knowledge Management . . . . . . . . . . . . . . . . . 24
2.3.2. The organizational context . . . . . . . . . . . . . . . . . . . . . . . . 24
2.3.3. The vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2.3.4. Guiding principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
2.3.5. Ad hoc infrastructures . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
2.3.6. Generic KM processes . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.3.7. Methods and tools for KM . . . . . . . . . . . . . . . . . . . . . . . . 34
vi Information and Knowledge System
2.4. A model for general knowledge management within the enterprise
(MGKME) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
2.4.1. Description of the MGKME . . . . . . . . . . . . . . . . . . . . . . . 36
2.4.2. State indicators for knowledge management systems. . . . . . . . . 40
2.5. Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
2.6. Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
CHAPTER 3. THE ENTERPRISE’S INFORMATION AND
KNOWLEDGE SYSTEM (EIKS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.1. Basic theories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
3.1.1. Three fundamental postulates. . . . . . . . . . . . . . . . . . . . . . . 45
3.1.2. Creation of individual and tacit knowledge . . . . . . . . . . . . . . 47
3.1.3. Commensurability of interpretative frameworks . . . . . . . . . . . 50
3.1.4. Conditions in which knowledge can be assimilated
to an object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
3.2. The enterprise’s information and knowledge system . . . . . . . . . . . 52
3.3. A knowledge system is not a knowledge-based system . . . . . . . . . . 54
3.4. Evolution of an EIKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.5. Representative example of an EIKS . . . . . . . . . . . . . . . . . . . . . 59
3.5.1. Presentation of the context . . . . . . . . . . . . . . . . . . . . . . . . 60
3.5.2. EIKS in this context . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.6. Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63
CONCLUSIONS AND PERSPECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . 65
APPENDIX. SEVEN GOLDEN RULES FOR SUCCESSFUL
KNOWLEDGE MANAGEMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
Preface
Communication is an essential aspect of human life, and the opportunities
provided by information and communications technologies are
unprecedented. Information in various forms can now be transmitted across
space and time. Paradoxically, to cite Feenberg [FEE 04], a distance has
been created between individuals, of “disposable experiences, that can be
turned on or off like water from a faucet”. Individuals have thus become
services, made available to others via a technical system, which can be
activated or deactivated at will.
Originally, the computer was not intended as a means of communication.
The Internet was not intended to serve as a conduit for this communication,
and information technology was not intended for anything other than the
automatic processing of information. Nevertheless, computers have become
ubiquitous: information technology is everywhere, in our jobs, televisions,
watches, telephones and even in our health. The quantities of information
involved, unimaginable in previous decades, are now treated using concepts
such as Big Data. Computers play an important role in our private lives, and
our private lives themselves have become computerized; with data located at
distant and unidentified points, they are in the clouds due to the use of
techniques such as cloud computing.
Man thus makes use of all available tools to fulfill the essential need for
communication. The use of information and communications technologies
should not obscure the substance of these exchanges: information.
Information which was previously passed from one person to another
through human interaction is now exchanged via computer protocols, which
aim to optimize systems interoperability without really considering human
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Preface ix
knowledge and the part played by individuals as holders of this knowledge.
To do this, a clear distinction should be made between “information” and
“knowledge”; moreover, it is crucial to be aware of the fact that information
can have different meanings, leading to the creation of different knowledge
for different individuals.
Pierre-Emmanuel ARDUIN,
Michel GRUNDSTEIN
and Camille ROSENTHAL-SABROUX
May 2015
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The only outward characteristic by which the males can be
distinguished from the females is the presence in the former of a
small white papilla on the ventral side of the 17th pair of legs (Pl. 47,
fig. 4). At the extremity of this papilla the modified crural gland of
the last leg opens by a slit-like aperture.
The generative orifice in both sexes is placed on the ventral surface
of the body, close to the anus, and between the two anal papillæ,
which are much more marked in small specimens than in large ones,
and in two cases (of females) were observed to bear rudimentary
claws.
1. The Male Organs. Pl. 53, fig. 43.
The male organs consist of a pair of testes (te), a pair of prostrates
(pr) and vasa deferentia (vd) and accessory glandular tubules (f).
All the above parts lie in the central compartment of the body-cavity.
In addition, the accessory glandular bodies or crural glands of the
last (17th) pair of legs [TN22]
are enlarged and prolonged into an
elongated tube placed in the lateral compartment of the body-cavity
(ag).
The arrangement of these parts represented in the figure appears
essentially that which Moseley has already described for this species.
The dilatations on the vasa deferentia, which he calls vesiculæ
seminales, is not so marked; nor can the peculiar spiral twisting of
this part of the vas deferens which he figures (No. 13) be made out
in this specimen. The testes are placed at different levels in the
median compartment of the body-cavity, and both lie on the same
side of the intestine (right side).
The arrangement of the terminal portions of the vas deferens is
precisely that described by Moseley. The right vas deferens passes
under both nerve-cords to join the left, and from the enlarged tube
(p), which, passing beneath the nerve-cord of its side, runs to the
external orifice. The enlarged terminal portion possesses thick
muscular walls, and possibly constitutes a spermatophore maker, as
has been shewn to be the case in P. N. Zealandiæ, by Moseley.
In some specimens a different arrangement obtains, in that the left
vas deferens passes under both nerve-cords to join the right.
In addition to the above structures, which are all described by
Moseley, there are a pair of small glandular tubes (f), which open
with the unpaired terminal portion of the vas deferens at the
generative orifice.
2. Female Organs. Pl. 52, fig. 33.
The female organs consist of a median unpaired ovary and a pair of
oviducts, which are dilated for a great part of their course to perform
a uterine function, and which open behind into a common vestibule
communicating directly with the exterior.
Ovary.—In the specimen figured the following is the arrangement:
The ovary lies rather to the dorsal side in the central compartment of
the body-cavity, and is attached to one of the longitudinal septa
separating this from the lateral compartment. It lies between the
penultimate and antepenultimate pair of legs.
The oviducts cross before opening to the exterior. The right oviduct
passes under the rectum, and the left over the rectum. They meet
by opening into a common vestibule, which in its turn opens to the
exterior immediately ventral to the anus. It has not been ascertained
how far this arrangement, which differs from that observed by
Moseley, is a normal one. The young undergo nearly the whole of
their development within the uterus. They possess at birth the full
number of appendages, and differ from the parent only in size and
colour.]
Notes on additional Glandular Bodies in the Legs
[Crural Glands].
1. They are present in all except the first.
2. They open externally to the nephridia (Pl. 51, fig. 20), except in
the fourth and fifth pairs of legs, in which they are internal.
3. A muscular layer covers the whole gland, consisting, I believe, of
an oblique circular layer.
4. The accessory gland in the male (fig. 43, ag) is probably a
modification of one of these organs.
[The structure and relations of these glands may be best understood
by reference to Pl. 51, fig. 20. Each consists of a dilated vesicular
portion (fgl) placed in the lateral compartment of the body-cavity in
the foot, and of a narrow duct leading to the exterior, and opening
on the ventral surface amongst the papillæ of the second row
(counting from the internal of the three foot pads—fig. 20, P).
The vesicular portion is lined by columnar cells, with very large oval
nuclei, while the duct is lined by cells similar to the epidermic cells,
with which they are continuous at the opening.
In the last (17th) leg of the males of this species, this gland (vide
above, note 4) possesses a slit-like opening placed at the apex of a
well-developed white papilla (Pl. 47, fig. 4). It is enormously
enlarged, and is prolonged forward as a long tubular gland, the
structure of which resembles that of the vesicles of the crural glands
in the other legs. This gland lies in the lateral compartment of the
body-cavity, and extends forward to the level of the 9th leg (Pl. 48,
fig. 8, and Pl. 53, fig. 43). It is described by Professor Balfour as the
accessory gland of the male, and is seen in section lying immediately
dorsal to the nerve-cord in fig. 20, ag.]
[570] Some material for this memoir was left by Prof. Balfour, which
will be published separately.
[571] Vide Spengel, “Oligognathus Bonelliæ."” Naples Mittheilungen,
Bd.III. pl. IV. fig. 52.
PART III.
The Development of Peripatus capensis.
[The remarkable discoveries about the early development of
Peripatus, which Balfour made in June last, shortly before starting
for Switzerland, have already been the subject of a short
communication to the Royal Society (Proc. Roy. Soc. No. 222, 1882).
They relate (1) to the blastopore, (2) to the origin of the mesoblast.
Balfour left no manuscript account or notes of his discovery in
connection with the drawings which he prepared in order to illustrate
it, but he spoke about it to Professor Ray Lankester and also to us,
and he further gave a short account of the matter in a private letter
to Professor Kleinenberg.
In this letter, which by the courtesy of Professor Kleinenberg we
have been permitted to see, he describes the blastopore as an
elongated slit-like structure extending along nearly the whole ventral
surface; and further states, as the result of his examination of the
few and ill-preserved embryos in his possession, that the mesoblast
appears to originate as paired outgrowths from the lips of the
blastopore.
The drawings left by Balfour in connection with the discoveries are
four in number: one of the entire embryo, shewing the slit-like
blastopore and the mesoblastic somites, the other three depicting
the transverse sections of the same embryo.
The first drawing (fig. 37), viz. that of the whole embryo, shews an
embryo of an oval shape, possessing six somites, whilst along the
middle of its ventral surface there are two slit-like openings, lying
parallel to the long axis of the body, and placed one behind the
other. The mesoblastic somites are arranged bilaterally in pairs, six
on either side of these slits. The following note in his handwriting is
attached to this drawing:
“Young larva of Peripatus capensis.—I could not make out for certain
which was the anterior end. Length 1.34 millimetres.”
Balfour's three remaining drawings (figs. 40-42) are, as already
stated, representations of transverse sections of the embryo figured
by him as a whole. They tend to shew, as he stated in the letter
referred to above, that the mesoblast originates as paired
outgrowths from the hypoblast, and that these outgrowths are
formed near the junction of the hypoblast with the epiblast at the
lips of the blastopore.
In fig. 42 the walls of the mesoblastic somites appear continuous
with those of the mesenteron near the blastopore.
In fig. 40, which is from a section a little in front of fig. 42, the walls
of the mesoblastic somites are independent of those of the
mesenteron.
Fig. 41 is from a section made in front of the region of the
blastopore.
In all the sections the epiblast lying over the somites is thickened,
while elsewhere it is formed of only one layer of cells; and this
thickening subsequently appears to give rise to the nervous system.
Balfour in his earlier investigations on the present subject found in
more advanced stages of the embryo the nerve-cords still scarcely
separated from the epiblast[572].
We have since found, in Balfour's material, embryos of a slightly
different age to that just described. Of these, three (figs. 34, 35, 36)
are younger, while one (fig. 38) is older than Balfour's embryo.
Stage A.—The youngest (fig. 34) is of a slightly oval form, and its
greatest length is .48 mm. It possesses a blastopore, which is
elongated in the direction of the long axis of the embryo, and is
slightly narrower in its middle than at either end. From one end of
the blastopore there is continued an opaque band. This we consider
to be the posterior end of the blastopore of the embryo. The
blastopore leads into the archenteron.
Stage B.—In the next stage (fig. 35) the embryo is elongate-oval in
form. Its length is .7 mm. The blastopore is elongated and slightly
narrowed in the middle. At the posterior end of the embryo there is
a mass of opaque tissue. On each side of the blastopore are three
mesoblastic somites. The length of the blastopore is .45 mm.
Stage C.—In the next stage (fig. 36) the features are much the same
as in the preceding. The length of the whole embryo is .9 mm.
The following were the measurements of an embryo of this stage
with five somites, but slightly younger than that from which fig. 36
was drawn.
Length of embryo .74 mm.
Length of blastopore .46 mm.
Distance between hind end of blastopore and hind end
of body .22 mm.
Distance between front end of body and front end of
blastopore .06 mm.
The somites have increased to five, and there are indications of a
sixth being budded off from the posterior mass of opaque tissue.
The median parts of the lips of the blastopore have come together
preparatory to the complete fusion by which the blastopore becomes
divided into two parts.
Stage D.—The next stage is Balfour's stage, and has been already
described.
The length is 1.34.
It will be observed, on comparing it with the preceding embryos,
that while the anterior pair of somites in figs. 35 and 36 lie at a
considerable distance from what we have called the anterior end of
the embryo (a), in the embryo now under consideration they are
placed at the anterior end of the body, one on each side of the
middle line. We cannot speak positively as to how they come there,
whether by a pushing forward of the anterior somites of the previous
stage, or by the formation of new somites anteriorly to those of the
previous stage.
In the next stage it is obvious that this anterior pair of somites has
been converted into the præoral lobes.
The anterior of the two openings to which the blastopore gives rise
is placed between the second pair of somites; we shall call it the
embryonic mouth. The posterior opening formed from the blastopore
is elongated, being dilated in front and continued back as a narrow
slit (?) to very near the hind end of the embryo, where it presents a
second slight dilatation. The anterior dilatation of the posterior open
region of the blastopore we shall call the embryonic anus.
Lately, but too late to be figured with this memoir, we have been
fortunate enough to find an embryo of apparently precisely the same
stage as fig. 37. We are able, therefore, to give a few more details
about the stage.
The measurements of this embryo were:
Length of whole embryo 1.32
mm.
Distance from front end of body to front end of mouth .32 mm.
Distance from embryonic mouth to hind end of
embryonic anus .52 mm.
Distance from hind end of embryonic anus to hind end
of body .45 mm.
Length of embryonic anus .2 mm.
Length of part of blastopore behind embryonic anus .2 mm.
Greatest width of embryo .64 mm.
Stage E.—In the next stage (figs. 38 and 39) the flexure of the hind
end of the body has considerably increased. The anterior opening of
the blastopore, the embryonic mouth, has increased remarkably in
size. It is circular, and is placed between the second pair of
mesoblastic somites. The anterior dilatation of the posterior opening
of the blastopore, the embryonic anus, has, like the anterior
opening, become much enlarged. It is circular, and is placed on the
concavity of the ventral flexure. From its hind end there is continued
to the hind end of the body a groove (shewn in fig. 39 as a dotted
line), which we take to be the remains of the posterior slit-like part
of the posterior opening of the blastopore of the preceding stage.
The posterior dilatation has disappeared. The embryo has apparently
about thirteen somites, which are still quite distinct from one
another, and apparently do not communicate at this stage with the
mesenteron.
The epiblast lying immediately over the somites is, as in the, earlier
stages, thickened, and the thickenings of the two sides join each
other in front of the embryonic mouth, where the anterior pair of
mesoblastic somites (the præoral lobes) are almost in contact.
The median ventral epiblast, i.e. the epiblast in the area, bounded
by the embryonic mouth and anus before and behind and by the
developing nerve-cords laterally, is extremely thin, and consists of
one layer of very flat cells. Over the dorsal surface of the body the
epiblast cells are cubical, and arranged in one layer.
Measurements of Embryo of Stage E.
Length of embryo 1.12 mm.
Greatest width .64 mm.
Distance from front end of embryonic mouth to hind
end of embryonic anus .48 mm.
Greatest length of embryonic mouth .16 mm.
Length between hind end of embryonic mouth and
front end of embryonic anus .29 mm.
These measurements were made with a micrometer eyepiece, with
the embryo lying on its back in the position of fig. 38, so that they
simply indicate the length of the straight line connecting the
respective points.
This is the last embryo of our series of young stages. The next and
oldest embryo was 3.2 mm. in length. It had ringed antennæ,
seventeen (?) pairs of legs, and was completely doubled upon itself,
as in Moseley's figure.
The pits into the cerebral ganglia and a mouth and anus were
present. There can be no doubt that the mouth and anus of this
embryo become the mouth and anus of the adult.
The important question as to the connection between the adult
mouth and anus, and the embryonic mouth and anus of the Stage E,
must, considering the great gap between Stage E and the next
oldest embryo, be left open. Meanwhile, we may point out that the
embryonic mouth of Stage E has exactly the same position as that of
the adult; but that the anus is considerably in front of the hind end
of the body in Stage E, while it is terminal in the adult.
If the embryonic mouth and anus do become the adult mouth and
anus, there would appear to be an entire absence of stomodæum
and proctodæum in Peripatus, unless the buccal cavity represents
the stomodæum. The latter is formed, as has been shewn by
Moseley, by a series of outgrowths round the simple mouth-opening
of the embryo, which enclosing the jaws give rise to the tumid lips of
the adult.
For our determination of the posterior and anterior ends of each of
these embryos, Stage A to E, we depend upon the opaque tissue
seen in each case at one end of the blastopore.
In Stage A it has the form of a band, extending backwards from the
blastopore.
In Stages B-D, it has the form of an opaque mass of tissue
occupying the whole hind end of the embryo, and extending a short
distance on either side of the posterior end of the blastopore.
This opacity is due in each case to a proliferation of cells of the
hypoblast, and, perhaps, of the epiblast (?).
There can be no doubt that the mesoblast so formed gives rise to
the great majority of the mesoblastic somites.
This posterior opacity is marked in Stage C by a slight longitudinal
groove extending backwards from the hind end of the blastopore.
This is difficult to see in surface views, and has not been
represented in the figure, but is easily seen in sections.
But in Stage D this groove has become very strongly marked in
surface views, and looks like a part of the original blastopore of
Stage C.
Sections shew that it does not lead into the archenteron, but only
into the mass of mesoblast which forms the posterior opacity. It
presents an extraordinary resemblance to the primitive streak of
vertebrates, and the ventral groove of insect embryos.
We think that there can be but little doubt that it is a part of the
original blastopore, which, on account of its late appearance (this
being due to the late development of the posterior part of the body
to which it belongs), does not acquire the normal relations of a
blastopore, but presents only those rudimentary features (deep
groove connected with origin of mesoblast) which the whole
blastopore of other tracheates presents.
We think it probable that the larval anus eventually shifts to the hind
end of the body, and gives rise to the adult anus. We reserve the
account of the internal structure of these embryos (Stages A-E) and
of the later stages for a subsequent memoir.
We may briefly summarise the more important facts of the early
development of Peripatus capensis, detailed in the preceding
account.
1. The greater part of the mesoblast is developed from the walls of
the archenteron.
2. The embryonic mouth and anus are derived from the respective
ends of the original blastopore, the middle part of the blastopore
closing up.
3. The embryonic mouth almost certainly becomes the adult mouth,
i.e. the aperture leading from the buccal cavity into the pharynx, the
two being in the same position. The embryonic anus is in front of
the position of the adult anus, but in all probability shifts back, and
persists as the adult anus.
4. The anterior pair of mesoblastic somites gives rise to the swellings
of the præoral lobes, and to the mesoblast of the head[573].
There is no need for us to enlarge upon the importance of these
facts. Their close bearing upon some of the most important
problems of morphology will be apparent to all, and we may with
advantage quote here some passages from Balfour's Comparative
Embryology, which shew that he himself long ago had anticipated
and in a sense predicted their discovery.
“Although the mesoblastic groove of insects is not a gastrula, it is
quite possible that it is the rudiment of a blastopore, the gastrula
corresponding to which has now vanished from development.”
(Comparative Embryology, Vol. I. p. 378, the original edition[574]
.)
“Tracheata.—Insecta. It (the mesoblast) grows inwards from the lips
of the germinal groove, which probably represents the remains of a
blastopore.” (Comparative Embryology, Vol. II. p. 291, the original
edition[575].)
“It is, therefore, highly probable that the paired ingrowths of the
mesoblast from the lips of the blastopore may have been, in the first
instance, derived from a pair of archenteric diverticula.”
(Comparative Embryology, Vol. II. p. 294, the original edition[576].)
The facts now recorded were discovered in June last, only a short
time before Balfour started for Switzerland; we know but little of the
new ideas which they called up in his mind. We can only point to
passages in his published works which seem to indicate the direction
which his speculations would have taken.
After speculating as to the probability of a genetic connection
between the circumoral nervous system of the Cœlenterata, and the
nervous system of Echinodermata, Platyhelminthes [TN23],
Chætopoda, Mollusca, &c., he goes on to say:
“A circumoral nerve-ring, if longitudinally extended, might
give rise to a pair of nerve-cords united in front and behind—
exactly such a nervous system, in fact, as is present in many
Nemertines (the Enopla and Pelagonemertes), in Peripatus
and in primitive molluscan types (Chiton, Fissurella, &c.).
From the lateral parts of this ring it would be easy to derive
the ventral cord of the Chætopoda and Arthropoda. It is
especially deserving of notice, in connection with the nervous
system of the above mentioned Nemertines and Peripatus,
that the commissure connecting the two nerve-cords behind
is placed on the dorsal side of the intestines. As is at once
obvious, by referring to the diagram (fig. 231 B), this is the
position this commissure ought, undoubtedly, to occupy if
derived from part of a nerve-ring which originally followed
more or less closely the ciliated edge of the body of the
supposed radiate ancestor.” (Comparative Embryology, Vol. II.
pp. 311, 312, the original edition[577]
.)
The facts of development here recorded give a strong additional
support to this latter view, and seem to render possible a
considerable extension of it along the same lines.]
List of Memoirs on Peripatus.
1. M. Lansdown G u i l d i n g . “An Account of a New Genus of Mollusca,” Zoological
Journal, Vol. II. p. 443, 1826.
2. M. A n d o u i n and M i l n e - E d wa rd s . “Classific. des Annélides et description
de celles qui habitent les côtes de France,” p. 411, Ann. Scien. Nat. ser. I. Vol. XXX.
1833.
3. M. G e r va i s . “Études p. servir à l'histoire naturelle des Myriapodes,” Ann.
Scien. Nat. ser. II. Vol. VII. 1837, p. 38.
4. W i e g m a n n . Wiegmann's Archiv, 1837.
5. H. M i l n e - E d wa rd s . “Note sur le Peripate juluforme,” Ann. Scien. Nat. ser. II.
Vol. XVIII. 1842.
6. B l a n c h a rd . “Sur l'organisation des Vers,” chap. IV. pp. 137-141, Ann. Scien.
Nat. ser. III. Vol. VIII. 1847.
7. Q u a t re fa g e s . “Anat. des Hermelles, note on,” p. 57, Ann. Scien. Nat. ser. III.
Vol. X. 1848.
8. Q u a t re fa g e s . Hist. Nat. des Annelés, 1865, Appendix, pp. 675-6.
9. De B l a i nv i l l e . Suppl. au Dict. des Sc. Nat. Vol. I.
10. Ed. G r u b e . “Untersuchungen üb. d. Bau von Peripatus Edwardsii,” Archiv für
Anat. und Physiol. 1853.
11. S a e n g e r. “Moskauer Naturforscher Sammlung,” Abth. Zool. 1869.
12. H. N. M o s e l e y. “On the Structure and Development of Peripatus capensis,”
Proc. Roy. Soc. No. 153, 1874.
13. H. N. M o s e l e y. “On the Structure and Development of Peripatus capensis,”
Phil. Trans. Vol. CLXIV. 1874.
14. H. N. M o s e l e y. “Remarks on Observations by Captain Hutton, Director of the
Otago Museum, on Peripatus novæ zealandiæ,” Ann. and Mag. of Nat. History,
Jan. 1877.
15. Captain H u tt o n . “Observations on Peripatus novæ zealandiæ,” Ann. and
Mag. of Nat. History, Nov. 1876.
16. F. M. B a l fo u r. “On Certain Points in the Anatomy of Peripatus capensis,”
Quart. Journ. of Micr. Science, Vol. XIX. 1879.
17. A. E r n s t . Nature, March 10th, 1881.
EXPLANATION OF PLATES 46-53[578].
Complete List of Reference Letters.
A. Anus. a. Dorso-lateral horn of white matter in brain. a.g. Accessory gland of
male (modified accessory leg gland). at. Antenna. at.n. Antennary nerve. b.
Ventro-lateral horn of white matter of brain. b.c. Body-cavity. bl. Blastopore. C.
Cutis. c. Postero-dorsal lobe of white matter of brain. c.g. Supra-œsophageal
ganglia. cl. Claw. c.m. Circular layer of muscles. co. Commissures between the
ventral nerve-cords. co.2. Second commissure between the ventral nerve-cords.
co1. 2. Mass of cells developed on second commissure. cor. Cornea. c.s.d.
Common duct for the two salivary glands. cu. Cuticle. d. Ventral protuberance of
brain. d.l.m. Dorsal longitudinal muscle of pharynx. d.n. Median dorsal nerve to
integument from supra-œsophageal ganglia. d.o. Muscular bands passing from the
ventro-lateral wall of the pharynx at the region of its opening into the buccal
cavity. E. Eye. E. Central lobe of white matter of brain. e.n. Nerves passing
outwards from the ventral cords. ep. Epidermis. ep.c. Epidermis cells. F.1, F.2, &c.
First and second pair of feet, &c. f. Small accessory glandular tubes of the male
generative apparatus. F.g. Ganglionic enlargement on ventral nerve-cord, from
which a pair of nerves to foot pass off. f.gl. Accessory foot-gland. F.n. Nerves to
feet. g.co. Commissures between the ventral nerve-cords containing ganglion
cells. g.o. Generative orifice. H. Heart. h. Cells in lateral division of body-cavity. hy.
Hypoblast. i.j. Inner jaw. j. Jaw. j.n. Nerves to jaws. L. Lips. l. Lens. l.b.c. Lateral
compartment of body-cavity. le. Jaw lever (cuticular prolongation of inner jaw lying
in a backwardly projecting diverticulum of the buccal cavity). l.m. Bands of
longitudinal muscles. M. Buccal cavity. M1. Median backward diverticulum of mouth
or common salivary duct which receives the salivary ducts. me. Mesenteron. mes.
Mesoblastic somite. m.l. Muscles of jaw lever. m.s. Sheets of muscle passing round
the side walls of pharynx to dorsal body-wall. od. Oviduct. œ. Œsophagus. œs.co.
Œsophageal commissures. o.f.g. Orifice of duct of foot-gland. o.j. Outer jaw. op.
Optic ganglion. op.n. Optic nerve. or.g. Ganglionic enlargements for oral papillæ.
or.n. Nerves to oral papillæ. or.p. Oral papillæ. o.s. Orifice of duct of segmental
organ. ov. Ovary. P. Pads on ventral side of foot. p. Common duct into which the
vasa deferentia open. p.c. Posterior lobe of brain. p.d.c. Posterior commissure
passing dorsal to rectum. p.f. Internal opening of nephridium into body-cavity. ph.
Pharynx. pi. Pigment in outer ends of epidermic cells. pi.r. Retinal pigment. p.n.
Nerves to feet. p.p. Primary papilla. pr. Prostate. R. Rectum. re. Retinal rods. R. m.
Muscle of claw. s. Vesicle of nephridium. s1. Part of 4th or 5th nephridium which
corresponds to vesicle of other nephridia. s.c.1. Region No. 1 of coiled tube of
nephridium. s.c.2. Region No. 2 of ditto. s.c.3. Region No. 3 of ditto. s.c.4. Region
No. 4 of ditto. s.d. Salivary duct. s.g. Salivary gland. sl.d. Reservoir of slime gland.
sl.g. Tubules of slime gland. s.o.1, 2, 3, &c. Nephridia of 1st, 2nd, &c., feet. s.o.f.
Terminal portion of nephridium. s.p. Secondary papilla. st. Stomach. st.e.
Epithelium of stomach. sy. Sympathetic nerve running in muscles of tongue and
pharynx. sy´. Origin of pharyngeal sympathetic nerves. T. Tongue. t. Teeth on
tongue. te. Testis. tr. Tracheæ. tr.c. Cells found along the course of the tracheæ.
tr.o. Tracheal stigma. tr.p. Tracheal pit. ut. Uterus. v.c. Ventral nerve cord. v.d. Vas
deferens. v.g. Imperfect ganglia of ventral cord.
Plate 46.
Fig. 1. Peripatus capensis, x 4; viewed from the dorsal surface. (From a drawing
by Miss Balfour.)
Plate 47.
Fig. 2. A left leg of Peripatus capensis, viewed from the ventral surface; x 30.
(From a drawing by Miss Balfour.)
Fig. 3. A right leg of Peripatus capensis, viewed from the front side. (From a
drawing by Miss Balfour.)
Fig. 4. The last left (17th) leg of a male Peripatus capensis, viewed from the
ventral side to shew the papilla at the apex of which the accessory gland of the
male, or enlarged crural gland, opens to the exterior. (From a drawing by Miss
Balfour.) Prof. Balfour left a rough drawing (not reproduced) shewing the papilla,
to which is appended the following note. “Figure shewing the accessory genital
gland of male, which opens on the last pair of legs by a papilla on the ventral side.
The papilla has got a slit-like aperture at its extremity.”
Fig. 5. Ventral view of head and oral region of Peripatus capensis. (From a drawing
by Miss Balfour.)
Plate 48.
Figs. 6 and 7 are from one drawing.
Fig. 6. Peripatus capensis dissected so as to shew the alimentary canal, slime
glands, and salivary glands; x 3. (From a drawing by Miss Balfour.)
Fig. 7. The anterior end of Fig. 6 enlarged; x 6. (From a drawing by Miss Balfour.)
The dissection is viewed from the ventral side, and the lips, L., have been cut
through in the middle line behind and pulled outwards, so as to expose the jaws,
j., which have been turned outwards, and the tongue, T., bearing a median row of
chitinous teeth, which branches behind into two. The junction of the salivary
ducts, s.d., and the opening of the median duct so formed into the buccal cavity is
also shewn. The muscular pharynx, extending back into the space between the 1st
and 2nd pairs of legs, is followed by a short tubular œsophagus. The latter opens
into the large stomach with plicated walls, extending almost to the hind end of the
animal. The stomach at its point of junction with the rectum presents an S-shaped
ventro-dorsal curve.
A. Anus. at. Antenna. F.1, F.2. First and second feet. j. Jaws. L. Lips. œ. Œsophagus.
or.p. Oral papilla. ph. Pharynx. R. Rectum. s.d. Salivary duct. s.g. Salivary gland.
sl.d. Slime reservoir. sl.g. Portion of tubules of slime gland. st. Stomach. T. Tongue
in roof of mouth.
Fig. 8. Peripatus capensis, x 4; male. (From a drawing by Miss Balfour.) Dissected
so as to shew the nervous system, slime glands, ducts of the latter passing into
the oral papilla, accessory glands opening on the last pair of legs (enlarged crural
glands), and segmental organs, viewed from dorsal surface. The first three pairs of
segmental organs consist only of the vesicle and duct leading to the exterior. The
fourth and fifth pairs are larger than the succeeding, and open externally to the
crural glands. The ventral nerve-cords unite behind dorsal to the rectum.
A. Anus. a.g. Accessory generative gland, or enlarged crural gland of the 17th leg.
at. Antenna. c.g. Supra-œsophageal ganglia with eyes. co. Commissures between
the ventral nerve-cords. d.n. Large median nerve to dorsal integument from hinder
part of brain. F.1, 2, &c. Feet. g.o. Generative orifice. œ. Œsophagus. œs.co.
Œsophageal commissures. or.p. Oral papilla. p.d.c. Posterior dorsal commissure
between the ventral nerve-cords. ph. Pharynx. p.n. Nerves to feet, one pair from
each ganglionic enlargement. sl.d. Reservoir of slime gland. sl.g. Tubules of slime
gland. s.o.1, 2, 3, &c. Segmental organs. v.c. Ventral nerve-cords. v.g. Imperfect
ganglia of ventral cords.
Figs. 9 and 10. Left jaw of Peripatus capensis (male), shewing reserve jaws. (From
a drawing by Miss Balfour.)
Fig. 9. Inner jaw.
Fig. 10. Outer jaw.
Plate 49.
Figs. 11-16. A series of six transverse sections through the head of Peripatus
capensis.
Fig. 11. The section is taken immediately behind the junction of the supra-
œsophageal ganglia, c.g., and passes through the buccal cavity, M., and jaws, o.j.
and i.j.
Fig. 12. The section is taken through the hinder part of the buccal cavity at the
level of the opening of the mouth into the pharynx and behind the jaws. The
cuticular rod-like continuation (le.) of the inner jaw lying in a backwardly directed
pit of the buccal cavity is shewn; on the right hand side the section passes
through the opening of this pit.
Fig. 13. The section passes through the front part of the pharynx, and shews the
opening into the latter of the median backward diverticulum of the mouth (M
1),
which receives the salivary ducts. It also shews the commencement of the ventral
nerve-cords, and the backwardly projecting lobes of the brain.
Fig. 14. The section passes through the anterior part of the pharynx at the level of
the second commissure (co.2), between the ventral nerve-trunks, and shews the
mass of cells developed on this commissure, which is in contact with the
epithelium of the backward continuation of the buccal cavity (M
1).
Fig. 15. Section through the point of junction of the salivary ducts with the median
oral diverticulum.
Fig. 16. Section behind the pharynx through the œsophagus.
b.c. Body-cavity. C. Cutis. c.b.c. Central compartment of body-cavity. c.g. Supra-
œsophageal ganglia. c.m. Layer of circular muscles. co. Commissure between
ventral nerve-cords. co. 2. Second commissure between the ventral nerve-cords.
co1. 2. Mass of cells developed on second commissure (probably sensory). c.s.d.
Common duct for the two salivary glands. d.l.m. Dorsal longitudinal muscles of
pharynx. d.o. Muscles serving to dilate the opening of the pharynx. Ep. Epidermis.
e.n. Nerve passing outwards from ventral nerve-cord. H. Heart. i.j. Inner jaw. j.p.
Jaw papillæ. L. Lips of buccal cavity. l.b.c. Lateral compartment of body-cavity. le.
Rod-like cuticular continuation of inner jaw, lying in a pit of the buccal cavity. l.m.
Bands of longitudinal muscles. M. Buccal cavity. M
1. Median backward continuation
of buccal cavity. m.l. Muscles of jaw lever. m.s. Muscular sheets passing from side
walls of pharynx to dorsal body-wall. œ. Œsophagus. œs.co. Œsophageal
commissures. o.j. Outer jaw. ph. Pharynx. s.d. Salivary duct. s.g. Salivary gland.
sl.d. Reservoir of slime gland. sy. Sympathetic nerves running in muscles of tongue
or pharynx. sy1. Origin of sympathetic nerves to pharynx. T. Tongue. v.c. Ventral
nerve-cords.
Figs. 17, 18. Two longitudinal horizontal sections through the head of Peripatus
capensis. Fig. 17 is the most ventral. They are both taken ventral to the cerebral
ganglia. In Fig. 17 dorsal tracheal pits are shewn with tracheæ passing off from
them. (Zeiss a a, Hartnack's camera.) C. Cutis. c.s.d. Common salivary duct. ep.
Epidermis. i.j. Inner jaw. M. Buccal cavity. M
1. Median backward diverticulum of
mouth. o.j. Outer jaw. s.d. Salivary ducts. T. Tongue. t. Teeth on tongue. tr.
Tracheæ. tr.p. Tracheal pits.
Plate 50.
Fig. 19. "A, B, C, D, E, F, G." Seven transverse sections illustrating the structure of the
supra-œsophageal ganglia. (Zeiss A, Hartnack's camera.) a. Dorso-lateral horn of
white matter. b. Ventro-lateral horn of white matter. c. Postero-dorsal lobe of white
matter. d. Ventral protuberance of brain. e. Central lobe of white matter. o.p. Optic
ganglion.
“A. Section through anterior portions of ganglia close to the origin of the antennary
nerve. B. Section a little in front of the point where the two ganglia unite. C.
Section close to anterior junction of two ganglia. D. Section through origin of optic
nerve on the right side. E. Section shewing origin of the optic nerve on the left
side. F. Section through the dorso-median lobe of white matter. G. Section near the
termination of the dorsal tongue of ganglion cells.”
Plate 51.
Fig. 20. Portion of a transverse section through the hinder part of Peripatus
capensis (male). The section passes through a leg, and shews the opening of the
segmental organ (o.s.), and of a crural gland, o.f.g., and the forward continuation
of the enlarged crural gland of the 17th leg (f.gl.). (Zeiss a a, Hartnack's camera.)
a.g. accessory gland of male (modified crural gland of last leg). C. Cutis. cl. Claw.
cu. Cuticle. ep. Epidermis. f.gl. Crural gland. h. Cells in lateral compartment of
body-cavity. o.f.g. Orifice of accessory foot gland. o.s. Opening of segmental
organ. P. Three spinous pads on ventral surface of foot. pr. Prostate. R.M. Retractor
muscle of claw. s. Vesicle of nephridium. s.c.i. Region No. 1 of coiled part of
nephridium. sl.g. Tubule of slime gland. s.o.t. Terminal portion of nephridium. st.
Stomach. st.e. Epithelium of stomach. v.c. Ventral nerve-cord. v.d. Vas deferens.
Fig. 21. “Longitudinal vertical section through the supra-œsophageal ganglion and
œsophageal commissures of Peripatus capensis. (Zeiss a a, Hartnack.)” at.
Antenna. e. Central lobe of white matter. j. Part of jaw. s.g. Salivary gland.
Fig. 22: drawn by Miss Balfour. Brain and anterior part of the ventral nerve-cords
of Peripatus capensis enlarged and viewed from the ventral surface. The paired
appendages (d) of the ventral surface of the brain are seen, and the pair of
sympathetic nerves (sy1) arising from the ventral surface of the hinder part.
From the commencement of the œsophageal commissures (œs.co.) pass off on
each side a pair of nerves to the jaws (j.n.).
The three anterior commissures between the ventral nerve-cords are placed close
together; immediately behind them the nerve-cords are swollen, to form the
ganglionic enlargements from which pass off to the oral papillæ a pair of large
nerves on each side (or.n.).
Behind this the cords present a series of enlargements, one pair for each pair of
feet, from which a pair of large nerves pass off on each side to the feet (p.n). at.n.
Antennary nerves. co. Commissures between ventral cords. d. Ventral appendages
of brain. E. Eye. e.n. Nerves passing outwards from ventral cord. F.g. Ganglionic
enlargements from which nerves to feet pass off. j.n. Nerves to jaws. or.g.
Ganglionic enlargement from which nerves to oral papillæ pass off. or.n. Nerves to
oral papillæ. p.c. Posterior lobe of brain. p.n. Nerves to feet. s.y. Sympathetic
nerves.
Fig. 23. “Longitudinal horizontal section through the head of Peripatus capensis,
shewing the structure of the brain, the antennary and optic nerves, &c. (Zeiss a a,
Hartnack's camera.)” at. Antenna. at.n. Antennary nerve. cor. Cornea. e. Central
mass of white matter. l. Lens. op.n. Optic nerve. ph. Pharynx. p.p. Primary papilla
covered with secondary papillæ and terminating in a long spine. sy. Pharyngeal
sympathetic nerves.
Fig. 24. “Eye of Peripatus capensis, as shewn in a longitudinal horizontal section
through the head. The figure is so far diagrammatic that the lens is represented as
filling up the whole space between the rods and the cornea. In the actual section
there is a considerable space between the parts, but this space is probably
artificial, being in part caused by the shrinkage of the lens and in part by the
action of the razor. (Zeiss C, Hartnack's camera.)” (It appears that the ganglionic
region of the eye is covered by a thin capsule, which is omitted in the figure.)
cor. Cornea. l. Lens. op. Optic ganglion. op.n. Optic nerve. pi.r. Pigment. Re. rods.
s.p. Secondary papillæ.
Fig. 25. Longitudinal horizontal section through the dorsal skin, shewing the
peculiar arrangement of the circular muscular fibres. (Zeiss A, Hartnack's camera.)
Plate 52.
Fig. 26. Portion of ventral cord of Peripatus capensis enlarged, shewing two
ganglionic enlargements and the origin of the nerves and commissures. (From a
drawing by Miss Balfour.)
co. Commissures. E.n. Nerves passing out from ventral cords. F.n. Nerves to feet.
g.co. Commissures between the ventral cords containing ganglion cells. v.g.
Ganglionic enlargements.
Fig. 27. Segmental organ from the 5th pair of legs of Peripatus capensis. This
nephridium resembles those of the 4th legs, and differs from all the others in its
large size and in the absence of any dilatation giving rise to a collecting vesicle on
its external portion (enlarged). The terminal portion has the same histological
characters as in the case of the hinder segmental organs. (From a drawing by Miss
Balfour.)
Fig. 28. Segmental organ or nephridium from the 9th pair of legs of Peripatus
capensis, shewing the external opening, the vesicle, the coiled portion and the
terminal portion with internal opening (enlarged). (From a drawing by Miss
Balfour.)
o.s. External opening of segmental organ. p.f. Internal opening of nephridium into
the body-cavity (lateral compartment). s. Vesicle of segmental organ. s1. Portion
of segmental organ of 4th and 5th legs, corresponding to vesicle of the other
nephridia. s.c.1. First or external portion of coiled tube of nephridium, lined by
columnar epithelium with small nuclei; the cells project for very different
distances, giving the inner boundary of this region a ragged appearance. s.c.2.
Region No. 2 of coiled tube of nephridium, lined by small closely-packed columnar
cells. s.c.3. Region No. 3 of coiled tube of segmental organ, lined by large flat cells
with large disc-shaped nuclei. s.c.4. Region No. 4 of coiled tube of nephridium;
this region is very short and lined by small columnar cells. s.o.t. Terminal portion
of nephridium.
Fig. 29. “Portion of nephridium of the hindermost leg of Peripatus capensis, seen
in longitudinal and vertical section. The figure is given to shew the peritoneal
funnel of the nephridium. Portions of the collecting sack (s.) and other parts are
also represented. (Zeiss B, Hartnack's camera.)”
p.f. Peritoneal funnel. s. Vesicle. s.c.1, s.c.2, s.c.3. Portions of coiled tube.
Fig. 30. “Section through a tracheal pit and diverging bundles of tracheal tubes”
taken transversely to the long axis of the body. (Zeiss E, oc. 2.) (From a rough
drawing by Prof. Balfour.)
tr. Tracheæ, shewing rudimentary spiral fibre. tr.c. Cells resembling those lining the
tracheal pits, which occur at intervals along the course of the tracheæ. tr.s.
Tracheal stigma. tr.p. Tracheal pit.
Fig. 31. “Sense organs and nerves attached from antenna of Peripatus capensis
(Zeiss, immersion 2, oc. 2.)” (From a rough drawing by Prof. Balfour.) The figure
shews the arrangement of the epidermis cells round the base of the spine. The
spine is seen to be continuous with the inner layer of the cuticle.
Fig. 32. Section through the skin of Peripatus capensis; it shews the secondary
papillæ covered with minute spinous tubercles and the relation of the epidermis to
them. (The cuticle in the process of cutting has been torn away from the
subjacent cells.) The cells of the epidermis are provided with large oval nuclei, and
there is a deposit of pigment in the outer ends of the cells. The granules in the
protoplasm of the inner ends of the cells are arranged in lines, so as to give a
streaked appearance. (Zeiss E, oc. 2.) (From a rough drawing by Prof. Balfour.)
c. Dermis. cu. Cuticle. ep.c. Epidermis cells. pi. Deposit of pigment in outer ends of
epidermis cells. s.p. Secondary papillæ.
Fig. 33. Female generative organs of Peripatus capensis, × 5. (From a rough
drawing by Prof. Balfour.) The following note was appended to this drawing:
“Ovary rather to dorsal side, lying in a central compartment of body-cavity and
attached to one of the longitudinal septa, dividing this from the lateral
compartment between the penultimate pair of legs and that next in front. The
oviducts cross before opening to the exterior, the right oviduct passing under the
rectum and the left over it. They meet by opening into a common vestibule, which
in its turn opens below the anus. On each side of it are a pair of short papillæ
(aborted feet?).”
F. 16, 17. Last two pairs of legs. od. Oviduct. ov. Ovary. ut. Uterus. v.c. Nerve-cord.
Plate 53.
Figs. 34-39. Five young embryos of Peripatus capensis; ventral view. All, excepting
Fig. 37, from drawings by Miss Balfour. In figures 34 to 38a denotes what is
probably the anterior extremity.
Fig. 34, Stage A. Youngest embryo found, with slightly elongated blastopore.
Fig. 35, Stage B. Embryo with three mesoblastic somites and elongated
blastopore. The external boundaries of the somites are not distinct.
Fig. 36, Stage C. Embryo with five somites. The blastopore is closing in its middle
portion.
Fig. 37, Stage D. The blastopore has completely closed in its middle portion, and
given rise to two openings, the future mouth and anus. (From a rough drawing left
by Professor Balfour.) (Zeiss A, Camera Oberhaus. on level of stage.)
The following note was appended to this drawing in his handwriting: “Young larva
of Peripatus capensis. I could not tell for certain which was the anterior end.
Length, 1.34 mm.”
Fig. 38, Stage E. Embryo with about thirteen mesoblastic somites in which the
flexure of the hind part of the body has commenced. The remains of the original
blastopore are present as the mouth, placed between the second pair of
mesoblastic somites, and the anus placed on the concavity of the commencing
flexure of the hind part of the body.
Fig. 39. Side view of same embryo.
Figs. 40-42. Drawings by Professor Balfour of three transverse sections through
the embryo from which fig. 36 was taken. (Zeiss c, Camera.) Figs. 40 and 42 pass
through the region of the blastopore.
bl. Blastopore. ep. Epiblast. hy. Hypoblast. me. Mesenteron. mes. Mesoblastic
somite.
Fig. 43. Male generative organs of Peripatus capensis, viewed from the dorsal
surface. (From a drawing by Miss Balfour.)
a.g. Enlarged crural glands of last pair of legs. F.16, 17. Last pairs of legs. f. Small
accessory glandular tubes. p. Common duct into which vasa deferentia open. p.r.
Prostate. te. Testes. v.c. Nerve-cord. v.d. Vas deferens.
[572] Comparative Embryology; original edition, Vol. I. p. 318. [This
edition, Vol. II. p. 385.]
[573] We have seen nothing in any of our sections which we can
identify as of so-called mesenchymatous origin.
[574] This edition, Vol. II. p. 457.
[575] This edition, Vol. III. p. 352.
[576] This edition, Vol. III. p. 356.
[577] This edition, Vol. III. pp. 378, 379.
[578] The explanations of the figures printed within inverted commas
are by Professor Balfour, the rest are by the Editors.
CAMBRIDGE: PRINTED BY C. J. CLAY, M.A., AND SON, AT THE
UNIVERSITY PRESS.
TRANSCRIBER'S NOTES:
Hyphens were spaced in ranges of small numbers to
ease readability, e.g., “1/2000-1/3000 of an inch”
was changed to “1/2000 - 1/3000 of an inch”.
Raised dots in numbers were converted to decimals.
Use of periods and commas in the abbreviations
within and referring to figures and plates is
inconsistent. Often, punctuation marks do not match
the illustrations to which they refer. Periods were
retained; commas were added to separate figure
numbers from abbreviations within the figure.
Spacing within the abbreviations was standardized.
Footnotes were renumbered sequentially, and were
moved to the end of the chapter. There is no anchor
for footnote 496; anchor was placed at the spot the
transcriber deemed it likely belonged. Footnote 351
incorrectly identifies the page number of the article
on urinogential organs of vertebrates. The number
provided in the original text of the footnote was
retained, but the link was corrected.
Changes for consistency within the text of the book:
body cavity to body-cavity
body wall to body-wall
choroid-slit to choroid slit
develope(s) to develop(s)
dog fish to dog-fish
Elasmobranchs to Elasmobranchii
Entwickelung to Entwicklung
head-fold to head fold
inter-renal to interrenal
juxta-position to juxtaposition
lenslike to lens-like
re-agent(s) to reagent(s)
omphalo-meseraic to omphalomeseraic
pleuroperitoneal to pleuro-peritoneal
proto-vertebra(æ) to protovertebra(æ)
re-appear to reappear
semi-lunar to semilunar
side-fold to side fold
spongework to sponge-work
subgerminal to sub-germinal
sub-intestinal to subintestinal
sub-kingdom to subkingdom
sub-notochordal to subnotochordal
suboesophageal to sub-oesophageal
supraoesophageal to supra-oesophageal
urino-genital to urinogenital
Urogenital-system to Urogenitalsystem, except
where cited as a title of a work.
Verwandschaft to Verwandtschaft
widespread to wide-spread
wood-cut(s) to woodcut(s)
zool. zoot. to zool.-zoot.
italics removed from eight instances of “vide”
italics, where missing, were added to loc. cit.,
i.e. and e.g.
Other changes:
[TN1] changed from 'reremainder'
[TN2] changed from 'on'
[TN3] changed from 'splachnopleure'
[TN4] changed from 'Sitzen.'
[TN5] changed from 'diffiulty'
[TN6] changed from 'it'
[TN7] changed from 'primive'
[TN8] and [TN10] changed from 'opthalmicus'
[TN9] Figure number is missing in the original.
[TN11] changed from 'Ureierernester'
[TN12] changed from 'vascula'
[TN13] changed from 'Metozoa'
[TN14] duplicate word 'of' removed
[TN15] changed from 'protodæum'
[TN16] changed from 'is it'
[TN17] changed from 'is is'
[TN18] changed from 'continous'
[TN19] changed from 'Zussammenhang'
[TN20] changed from 'Tranverse'
[TN21] changed from 'odontophor'
[TN22] changed from 'lens'
[TN23] changed from 'Platyelminthes'
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  • 9. Advances in Information Systems Set coordinated by Camille Rosenthal-Sabroux Volume 2 Information and Knowledge System Pierre-Emmanuel Arduin Michel Grundstein Camille Rosenthal-Sabroux
  • 10. First published 2015 in Great Britain and the United States by ISTE Ltd and John Wiley & Sons, Inc. Apart from any fair dealing for the purposes of research or private study, or criticism or review, as permitted under the Copyright, Designs and Patents Act 1988, this publication may only be reproduced, stored or transmitted, in any form or by any means, with the prior permission in writing of the publishers, or in the case of reprographic reproduction in accordance with the terms and licenses issued by the CLA. Enquiries concerning reproduction outside these terms should be sent to the publishers at the undermentioned address: ISTE Ltd John Wiley & Sons, Inc. 27-37 St George’s Road 111 River Street London SW19 4EU Hoboken, NJ 07030 UK USA www.iste.co.uk www.wiley.com © ISTE Ltd 2015 The rights of Pierre-Emmanuel Arduin, Michel Grundstein and Camille Rosenthal-Sabroux to be identified as the author of this work have been asserted by them in accordance with the Copyright, Designs and Patents Act 1988. Library of Congress Control Number: 2015940032 British Library Cataloguing-in-Publication Data A CIP record for this book is available from the British Library ISBN 978-1-84821-752-2
  • 11. Contents PREFACE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xi CHAPTER 1. INFORMATION SYSTEMS AND DIGITAL TECHNOLOGY . . . . . . 1 1.1. The concept of information systems . . . . . . . . . . . . . . . . . . . . . 1 1.2. History of the concept of information systems . . . . . . . . . . . . . . . 5 1.2.1. The centralized processing stage (1950s–1960s) . . . . . . . . . . 5 1.2.2. The data decentralization stage (1970s–1990s) . . . . . . . . . . . 6 1.2.3. The interoperability and standardization stage (1990s) . . . . . . . 6 1.2.4. The universality and globalization stage (2000 onward) . . . . . . 7 1.3. What is “digital” technology? . . . . . . . . . . . . . . . . . . . . . . . . 9 1.4. Information systems and digital technology for business . . . . . . . . . 11 1.5. Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 CHAPTER 2. KNOWLEDGE MANAGEMENT. . . . . . . . . . . . . . . . . . . . . . 17 2.1. Historical overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.2. Knowledge Management: two dominant approaches . . . . . . . . . . . 20 2.2.1. The technological approach. . . . . . . . . . . . . . . . . . . . . . . . 21 2.2.2. The managerial and sociotechnical approach to KM . . . . . . . . . 22 2.3. Specific management principles for KM. . . . . . . . . . . . . . . . . . . 23 2.3.1. Definition of Knowledge Management . . . . . . . . . . . . . . . . . 24 2.3.2. The organizational context . . . . . . . . . . . . . . . . . . . . . . . . 24 2.3.3. The vision . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 2.3.4. Guiding principles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2.3.5. Ad hoc infrastructures . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 2.3.6. Generic KM processes . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 2.3.7. Methods and tools for KM . . . . . . . . . . . . . . . . . . . . . . . . 34
  • 12. vi Information and Knowledge System 2.4. A model for general knowledge management within the enterprise (MGKME) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 2.4.1. Description of the MGKME . . . . . . . . . . . . . . . . . . . . . . . 36 2.4.2. State indicators for knowledge management systems. . . . . . . . . 40 2.5. Conclusions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 2.6. Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 CHAPTER 3. THE ENTERPRISE’S INFORMATION AND KNOWLEDGE SYSTEM (EIKS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 3.1. Basic theories. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 3.1.1. Three fundamental postulates. . . . . . . . . . . . . . . . . . . . . . . 45 3.1.2. Creation of individual and tacit knowledge . . . . . . . . . . . . . . 47 3.1.3. Commensurability of interpretative frameworks . . . . . . . . . . . 50 3.1.4. Conditions in which knowledge can be assimilated to an object . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3.2. The enterprise’s information and knowledge system . . . . . . . . . . . 52 3.3. A knowledge system is not a knowledge-based system . . . . . . . . . . 54 3.4. Evolution of an EIKS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59 3.5. Representative example of an EIKS . . . . . . . . . . . . . . . . . . . . . 59 3.5.1. Presentation of the context . . . . . . . . . . . . . . . . . . . . . . . . 60 3.5.2. EIKS in this context . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61 3.6. Key points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63 CONCLUSIONS AND PERSPECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . 65 APPENDIX. SEVEN GOLDEN RULES FOR SUCCESSFUL KNOWLEDGE MANAGEMENT. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69 BIBLIOGRAPHY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75 INDEX . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
  • 13. Preface Communication is an essential aspect of human life, and the opportunities provided by information and communications technologies are unprecedented. Information in various forms can now be transmitted across space and time. Paradoxically, to cite Feenberg [FEE 04], a distance has been created between individuals, of “disposable experiences, that can be turned on or off like water from a faucet”. Individuals have thus become services, made available to others via a technical system, which can be activated or deactivated at will. Originally, the computer was not intended as a means of communication. The Internet was not intended to serve as a conduit for this communication, and information technology was not intended for anything other than the automatic processing of information. Nevertheless, computers have become ubiquitous: information technology is everywhere, in our jobs, televisions, watches, telephones and even in our health. The quantities of information involved, unimaginable in previous decades, are now treated using concepts such as Big Data. Computers play an important role in our private lives, and our private lives themselves have become computerized; with data located at distant and unidentified points, they are in the clouds due to the use of techniques such as cloud computing. Man thus makes use of all available tools to fulfill the essential need for communication. The use of information and communications technologies should not obscure the substance of these exchanges: information. Information which was previously passed from one person to another through human interaction is now exchanged via computer protocols, which aim to optimize systems interoperability without really considering human
  • 14. viii Info interacti simple i way as or the n constan transcrib Figure 1 Ptolem lord”: e This commun ensuring interpre become system aspects: own rig has a m technolo Any informa contact, organiza technolo acquire individu informa concept rmation and Kn ion; these i information. a prehistoric neumes of G tly confront bed informat 1. Information c my, the ever-livi extract from the book aims nication tech g that the etation and e informatio may be bas : users them ght. These us meaning for ogical artifac attempt to l ation system , would m ation [FEE ogical devic all lead to uals and th ation transm t of informat nowledge System nteractions Information c painting on Gregorian c ted with th tion (see Fig can only become ing, beloved of P e Rosetta Stone to highlight hnology (ICT correct me the creation n and know ed on ICT, selves play a sers process, them, some cts. limit informa using comp most probabl 04, p. 180] ces, the ease more direct, he digital i mitted within tion and kno m involve the n alone is sim n the wall of chant in a h e challenge gure 1). e knowledge fo Ptah, the god E [FER 68, p. 43 t the advanta T) both in ter eaning is t n of knowle wledge syst it cannot be a role, acting store and tr ething which ation exchan puter technol ly be seen . However, e of use and , frequent an information an organiz owledge syst exchange o mply a transc a cave, hiero hymnal. Hist s involved r you if it has a Epiphanes Euch ] (source: Nati ages offered rms of inform ransmitted, edge. Inform tems. Althou e reduced to g as system ansmit inform h does not o nge to the fra logy, to the n as “totali the number d the social nd essential system. M zation, this b tem, which h of much mo cription, in t oglyphs on a torians of to in interpret a meaning for yo haristos, most g ional Library of by informa mation excha allowing b mation syste ugh an info o these techn components mation, but occur in the amework of exclusion o itarian” with r and availa character th interaction Moving beyo book introdu highlights the ore than the same papyrus oday are ting this ou. “King gracious f France) ation and ange and eneficial ms thus ormation nological s in their this data case of a digital f human hin any ability of hey may between ond the uces the e role of
  • 15. Preface ix knowledge and the part played by individuals as holders of this knowledge. To do this, a clear distinction should be made between “information” and “knowledge”; moreover, it is crucial to be aware of the fact that information can have different meanings, leading to the creation of different knowledge for different individuals. Pierre-Emmanuel ARDUIN, Michel GRUNDSTEIN and Camille ROSENTHAL-SABROUX May 2015
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  • 17. The only outward characteristic by which the males can be distinguished from the females is the presence in the former of a small white papilla on the ventral side of the 17th pair of legs (Pl. 47, fig. 4). At the extremity of this papilla the modified crural gland of the last leg opens by a slit-like aperture. The generative orifice in both sexes is placed on the ventral surface of the body, close to the anus, and between the two anal papillæ, which are much more marked in small specimens than in large ones, and in two cases (of females) were observed to bear rudimentary claws. 1. The Male Organs. Pl. 53, fig. 43. The male organs consist of a pair of testes (te), a pair of prostrates (pr) and vasa deferentia (vd) and accessory glandular tubules (f). All the above parts lie in the central compartment of the body-cavity. In addition, the accessory glandular bodies or crural glands of the last (17th) pair of legs [TN22] are enlarged and prolonged into an elongated tube placed in the lateral compartment of the body-cavity (ag). The arrangement of these parts represented in the figure appears essentially that which Moseley has already described for this species. The dilatations on the vasa deferentia, which he calls vesiculæ seminales, is not so marked; nor can the peculiar spiral twisting of this part of the vas deferens which he figures (No. 13) be made out in this specimen. The testes are placed at different levels in the median compartment of the body-cavity, and both lie on the same side of the intestine (right side). The arrangement of the terminal portions of the vas deferens is precisely that described by Moseley. The right vas deferens passes under both nerve-cords to join the left, and from the enlarged tube (p), which, passing beneath the nerve-cord of its side, runs to the external orifice. The enlarged terminal portion possesses thick
  • 18. muscular walls, and possibly constitutes a spermatophore maker, as has been shewn to be the case in P. N. Zealandiæ, by Moseley. In some specimens a different arrangement obtains, in that the left vas deferens passes under both nerve-cords to join the right. In addition to the above structures, which are all described by Moseley, there are a pair of small glandular tubes (f), which open with the unpaired terminal portion of the vas deferens at the generative orifice. 2. Female Organs. Pl. 52, fig. 33. The female organs consist of a median unpaired ovary and a pair of oviducts, which are dilated for a great part of their course to perform a uterine function, and which open behind into a common vestibule communicating directly with the exterior. Ovary.—In the specimen figured the following is the arrangement: The ovary lies rather to the dorsal side in the central compartment of the body-cavity, and is attached to one of the longitudinal septa separating this from the lateral compartment. It lies between the penultimate and antepenultimate pair of legs. The oviducts cross before opening to the exterior. The right oviduct passes under the rectum, and the left over the rectum. They meet by opening into a common vestibule, which in its turn opens to the exterior immediately ventral to the anus. It has not been ascertained how far this arrangement, which differs from that observed by Moseley, is a normal one. The young undergo nearly the whole of their development within the uterus. They possess at birth the full number of appendages, and differ from the parent only in size and colour.] Notes on additional Glandular Bodies in the Legs [Crural Glands].
  • 19. 1. They are present in all except the first. 2. They open externally to the nephridia (Pl. 51, fig. 20), except in the fourth and fifth pairs of legs, in which they are internal. 3. A muscular layer covers the whole gland, consisting, I believe, of an oblique circular layer. 4. The accessory gland in the male (fig. 43, ag) is probably a modification of one of these organs. [The structure and relations of these glands may be best understood by reference to Pl. 51, fig. 20. Each consists of a dilated vesicular portion (fgl) placed in the lateral compartment of the body-cavity in the foot, and of a narrow duct leading to the exterior, and opening on the ventral surface amongst the papillæ of the second row (counting from the internal of the three foot pads—fig. 20, P). The vesicular portion is lined by columnar cells, with very large oval nuclei, while the duct is lined by cells similar to the epidermic cells, with which they are continuous at the opening. In the last (17th) leg of the males of this species, this gland (vide above, note 4) possesses a slit-like opening placed at the apex of a well-developed white papilla (Pl. 47, fig. 4). It is enormously enlarged, and is prolonged forward as a long tubular gland, the structure of which resembles that of the vesicles of the crural glands in the other legs. This gland lies in the lateral compartment of the body-cavity, and extends forward to the level of the 9th leg (Pl. 48, fig. 8, and Pl. 53, fig. 43). It is described by Professor Balfour as the accessory gland of the male, and is seen in section lying immediately dorsal to the nerve-cord in fig. 20, ag.] [570] Some material for this memoir was left by Prof. Balfour, which will be published separately. [571] Vide Spengel, “Oligognathus Bonelliæ."” Naples Mittheilungen, Bd.III. pl. IV. fig. 52.
  • 20. PART III. The Development of Peripatus capensis. [The remarkable discoveries about the early development of Peripatus, which Balfour made in June last, shortly before starting for Switzerland, have already been the subject of a short communication to the Royal Society (Proc. Roy. Soc. No. 222, 1882). They relate (1) to the blastopore, (2) to the origin of the mesoblast. Balfour left no manuscript account or notes of his discovery in connection with the drawings which he prepared in order to illustrate it, but he spoke about it to Professor Ray Lankester and also to us, and he further gave a short account of the matter in a private letter to Professor Kleinenberg. In this letter, which by the courtesy of Professor Kleinenberg we have been permitted to see, he describes the blastopore as an elongated slit-like structure extending along nearly the whole ventral surface; and further states, as the result of his examination of the few and ill-preserved embryos in his possession, that the mesoblast appears to originate as paired outgrowths from the lips of the blastopore. The drawings left by Balfour in connection with the discoveries are four in number: one of the entire embryo, shewing the slit-like blastopore and the mesoblastic somites, the other three depicting the transverse sections of the same embryo. The first drawing (fig. 37), viz. that of the whole embryo, shews an embryo of an oval shape, possessing six somites, whilst along the middle of its ventral surface there are two slit-like openings, lying parallel to the long axis of the body, and placed one behind the other. The mesoblastic somites are arranged bilaterally in pairs, six on either side of these slits. The following note in his handwriting is attached to this drawing:
  • 21. “Young larva of Peripatus capensis.—I could not make out for certain which was the anterior end. Length 1.34 millimetres.” Balfour's three remaining drawings (figs. 40-42) are, as already stated, representations of transverse sections of the embryo figured by him as a whole. They tend to shew, as he stated in the letter referred to above, that the mesoblast originates as paired outgrowths from the hypoblast, and that these outgrowths are formed near the junction of the hypoblast with the epiblast at the lips of the blastopore. In fig. 42 the walls of the mesoblastic somites appear continuous with those of the mesenteron near the blastopore. In fig. 40, which is from a section a little in front of fig. 42, the walls of the mesoblastic somites are independent of those of the mesenteron. Fig. 41 is from a section made in front of the region of the blastopore. In all the sections the epiblast lying over the somites is thickened, while elsewhere it is formed of only one layer of cells; and this thickening subsequently appears to give rise to the nervous system. Balfour in his earlier investigations on the present subject found in more advanced stages of the embryo the nerve-cords still scarcely separated from the epiblast[572]. We have since found, in Balfour's material, embryos of a slightly different age to that just described. Of these, three (figs. 34, 35, 36) are younger, while one (fig. 38) is older than Balfour's embryo. Stage A.—The youngest (fig. 34) is of a slightly oval form, and its greatest length is .48 mm. It possesses a blastopore, which is elongated in the direction of the long axis of the embryo, and is slightly narrower in its middle than at either end. From one end of the blastopore there is continued an opaque band. This we consider
  • 22. to be the posterior end of the blastopore of the embryo. The blastopore leads into the archenteron. Stage B.—In the next stage (fig. 35) the embryo is elongate-oval in form. Its length is .7 mm. The blastopore is elongated and slightly narrowed in the middle. At the posterior end of the embryo there is a mass of opaque tissue. On each side of the blastopore are three mesoblastic somites. The length of the blastopore is .45 mm. Stage C.—In the next stage (fig. 36) the features are much the same as in the preceding. The length of the whole embryo is .9 mm. The following were the measurements of an embryo of this stage with five somites, but slightly younger than that from which fig. 36 was drawn. Length of embryo .74 mm. Length of blastopore .46 mm. Distance between hind end of blastopore and hind end of body .22 mm. Distance between front end of body and front end of blastopore .06 mm. The somites have increased to five, and there are indications of a sixth being budded off from the posterior mass of opaque tissue. The median parts of the lips of the blastopore have come together preparatory to the complete fusion by which the blastopore becomes divided into two parts. Stage D.—The next stage is Balfour's stage, and has been already described. The length is 1.34. It will be observed, on comparing it with the preceding embryos, that while the anterior pair of somites in figs. 35 and 36 lie at a considerable distance from what we have called the anterior end of the embryo (a), in the embryo now under consideration they are
  • 23. placed at the anterior end of the body, one on each side of the middle line. We cannot speak positively as to how they come there, whether by a pushing forward of the anterior somites of the previous stage, or by the formation of new somites anteriorly to those of the previous stage. In the next stage it is obvious that this anterior pair of somites has been converted into the præoral lobes. The anterior of the two openings to which the blastopore gives rise is placed between the second pair of somites; we shall call it the embryonic mouth. The posterior opening formed from the blastopore is elongated, being dilated in front and continued back as a narrow slit (?) to very near the hind end of the embryo, where it presents a second slight dilatation. The anterior dilatation of the posterior open region of the blastopore we shall call the embryonic anus. Lately, but too late to be figured with this memoir, we have been fortunate enough to find an embryo of apparently precisely the same stage as fig. 37. We are able, therefore, to give a few more details about the stage. The measurements of this embryo were: Length of whole embryo 1.32 mm. Distance from front end of body to front end of mouth .32 mm. Distance from embryonic mouth to hind end of embryonic anus .52 mm. Distance from hind end of embryonic anus to hind end of body .45 mm. Length of embryonic anus .2 mm. Length of part of blastopore behind embryonic anus .2 mm. Greatest width of embryo .64 mm.
  • 24. Stage E.—In the next stage (figs. 38 and 39) the flexure of the hind end of the body has considerably increased. The anterior opening of the blastopore, the embryonic mouth, has increased remarkably in size. It is circular, and is placed between the second pair of mesoblastic somites. The anterior dilatation of the posterior opening of the blastopore, the embryonic anus, has, like the anterior opening, become much enlarged. It is circular, and is placed on the concavity of the ventral flexure. From its hind end there is continued to the hind end of the body a groove (shewn in fig. 39 as a dotted line), which we take to be the remains of the posterior slit-like part of the posterior opening of the blastopore of the preceding stage. The posterior dilatation has disappeared. The embryo has apparently about thirteen somites, which are still quite distinct from one another, and apparently do not communicate at this stage with the mesenteron. The epiblast lying immediately over the somites is, as in the, earlier stages, thickened, and the thickenings of the two sides join each other in front of the embryonic mouth, where the anterior pair of mesoblastic somites (the præoral lobes) are almost in contact. The median ventral epiblast, i.e. the epiblast in the area, bounded by the embryonic mouth and anus before and behind and by the developing nerve-cords laterally, is extremely thin, and consists of one layer of very flat cells. Over the dorsal surface of the body the epiblast cells are cubical, and arranged in one layer. Measurements of Embryo of Stage E. Length of embryo 1.12 mm. Greatest width .64 mm. Distance from front end of embryonic mouth to hind end of embryonic anus .48 mm. Greatest length of embryonic mouth .16 mm. Length between hind end of embryonic mouth and front end of embryonic anus .29 mm.
  • 25. These measurements were made with a micrometer eyepiece, with the embryo lying on its back in the position of fig. 38, so that they simply indicate the length of the straight line connecting the respective points. This is the last embryo of our series of young stages. The next and oldest embryo was 3.2 mm. in length. It had ringed antennæ, seventeen (?) pairs of legs, and was completely doubled upon itself, as in Moseley's figure. The pits into the cerebral ganglia and a mouth and anus were present. There can be no doubt that the mouth and anus of this embryo become the mouth and anus of the adult. The important question as to the connection between the adult mouth and anus, and the embryonic mouth and anus of the Stage E, must, considering the great gap between Stage E and the next oldest embryo, be left open. Meanwhile, we may point out that the embryonic mouth of Stage E has exactly the same position as that of the adult; but that the anus is considerably in front of the hind end of the body in Stage E, while it is terminal in the adult. If the embryonic mouth and anus do become the adult mouth and anus, there would appear to be an entire absence of stomodæum and proctodæum in Peripatus, unless the buccal cavity represents the stomodæum. The latter is formed, as has been shewn by Moseley, by a series of outgrowths round the simple mouth-opening of the embryo, which enclosing the jaws give rise to the tumid lips of the adult. For our determination of the posterior and anterior ends of each of these embryos, Stage A to E, we depend upon the opaque tissue seen in each case at one end of the blastopore. In Stage A it has the form of a band, extending backwards from the blastopore.
  • 26. In Stages B-D, it has the form of an opaque mass of tissue occupying the whole hind end of the embryo, and extending a short distance on either side of the posterior end of the blastopore. This opacity is due in each case to a proliferation of cells of the hypoblast, and, perhaps, of the epiblast (?). There can be no doubt that the mesoblast so formed gives rise to the great majority of the mesoblastic somites. This posterior opacity is marked in Stage C by a slight longitudinal groove extending backwards from the hind end of the blastopore. This is difficult to see in surface views, and has not been represented in the figure, but is easily seen in sections. But in Stage D this groove has become very strongly marked in surface views, and looks like a part of the original blastopore of Stage C. Sections shew that it does not lead into the archenteron, but only into the mass of mesoblast which forms the posterior opacity. It presents an extraordinary resemblance to the primitive streak of vertebrates, and the ventral groove of insect embryos. We think that there can be but little doubt that it is a part of the original blastopore, which, on account of its late appearance (this being due to the late development of the posterior part of the body to which it belongs), does not acquire the normal relations of a blastopore, but presents only those rudimentary features (deep groove connected with origin of mesoblast) which the whole blastopore of other tracheates presents. We think it probable that the larval anus eventually shifts to the hind end of the body, and gives rise to the adult anus. We reserve the account of the internal structure of these embryos (Stages A-E) and of the later stages for a subsequent memoir. We may briefly summarise the more important facts of the early development of Peripatus capensis, detailed in the preceding
  • 27. account. 1. The greater part of the mesoblast is developed from the walls of the archenteron. 2. The embryonic mouth and anus are derived from the respective ends of the original blastopore, the middle part of the blastopore closing up. 3. The embryonic mouth almost certainly becomes the adult mouth, i.e. the aperture leading from the buccal cavity into the pharynx, the two being in the same position. The embryonic anus is in front of the position of the adult anus, but in all probability shifts back, and persists as the adult anus. 4. The anterior pair of mesoblastic somites gives rise to the swellings of the præoral lobes, and to the mesoblast of the head[573]. There is no need for us to enlarge upon the importance of these facts. Their close bearing upon some of the most important problems of morphology will be apparent to all, and we may with advantage quote here some passages from Balfour's Comparative Embryology, which shew that he himself long ago had anticipated and in a sense predicted their discovery. “Although the mesoblastic groove of insects is not a gastrula, it is quite possible that it is the rudiment of a blastopore, the gastrula corresponding to which has now vanished from development.” (Comparative Embryology, Vol. I. p. 378, the original edition[574] .) “Tracheata.—Insecta. It (the mesoblast) grows inwards from the lips of the germinal groove, which probably represents the remains of a blastopore.” (Comparative Embryology, Vol. II. p. 291, the original edition[575].) “It is, therefore, highly probable that the paired ingrowths of the mesoblast from the lips of the blastopore may have been, in the first instance, derived from a pair of archenteric diverticula.” (Comparative Embryology, Vol. II. p. 294, the original edition[576].)
  • 28. The facts now recorded were discovered in June last, only a short time before Balfour started for Switzerland; we know but little of the new ideas which they called up in his mind. We can only point to passages in his published works which seem to indicate the direction which his speculations would have taken. After speculating as to the probability of a genetic connection between the circumoral nervous system of the Cœlenterata, and the nervous system of Echinodermata, Platyhelminthes [TN23], Chætopoda, Mollusca, &c., he goes on to say: “A circumoral nerve-ring, if longitudinally extended, might give rise to a pair of nerve-cords united in front and behind— exactly such a nervous system, in fact, as is present in many Nemertines (the Enopla and Pelagonemertes), in Peripatus and in primitive molluscan types (Chiton, Fissurella, &c.). From the lateral parts of this ring it would be easy to derive the ventral cord of the Chætopoda and Arthropoda. It is especially deserving of notice, in connection with the nervous system of the above mentioned Nemertines and Peripatus, that the commissure connecting the two nerve-cords behind is placed on the dorsal side of the intestines. As is at once obvious, by referring to the diagram (fig. 231 B), this is the position this commissure ought, undoubtedly, to occupy if derived from part of a nerve-ring which originally followed more or less closely the ciliated edge of the body of the supposed radiate ancestor.” (Comparative Embryology, Vol. II. pp. 311, 312, the original edition[577] .) The facts of development here recorded give a strong additional support to this latter view, and seem to render possible a considerable extension of it along the same lines.] List of Memoirs on Peripatus.
  • 29. 1. M. Lansdown G u i l d i n g . “An Account of a New Genus of Mollusca,” Zoological Journal, Vol. II. p. 443, 1826. 2. M. A n d o u i n and M i l n e - E d wa rd s . “Classific. des Annélides et description de celles qui habitent les côtes de France,” p. 411, Ann. Scien. Nat. ser. I. Vol. XXX. 1833. 3. M. G e r va i s . “Études p. servir à l'histoire naturelle des Myriapodes,” Ann. Scien. Nat. ser. II. Vol. VII. 1837, p. 38. 4. W i e g m a n n . Wiegmann's Archiv, 1837. 5. H. M i l n e - E d wa rd s . “Note sur le Peripate juluforme,” Ann. Scien. Nat. ser. II. Vol. XVIII. 1842. 6. B l a n c h a rd . “Sur l'organisation des Vers,” chap. IV. pp. 137-141, Ann. Scien. Nat. ser. III. Vol. VIII. 1847. 7. Q u a t re fa g e s . “Anat. des Hermelles, note on,” p. 57, Ann. Scien. Nat. ser. III. Vol. X. 1848. 8. Q u a t re fa g e s . Hist. Nat. des Annelés, 1865, Appendix, pp. 675-6. 9. De B l a i nv i l l e . Suppl. au Dict. des Sc. Nat. Vol. I. 10. Ed. G r u b e . “Untersuchungen üb. d. Bau von Peripatus Edwardsii,” Archiv für Anat. und Physiol. 1853. 11. S a e n g e r. “Moskauer Naturforscher Sammlung,” Abth. Zool. 1869. 12. H. N. M o s e l e y. “On the Structure and Development of Peripatus capensis,” Proc. Roy. Soc. No. 153, 1874. 13. H. N. M o s e l e y. “On the Structure and Development of Peripatus capensis,” Phil. Trans. Vol. CLXIV. 1874. 14. H. N. M o s e l e y. “Remarks on Observations by Captain Hutton, Director of the Otago Museum, on Peripatus novæ zealandiæ,” Ann. and Mag. of Nat. History, Jan. 1877. 15. Captain H u tt o n . “Observations on Peripatus novæ zealandiæ,” Ann. and Mag. of Nat. History, Nov. 1876. 16. F. M. B a l fo u r. “On Certain Points in the Anatomy of Peripatus capensis,” Quart. Journ. of Micr. Science, Vol. XIX. 1879. 17. A. E r n s t . Nature, March 10th, 1881.
  • 30. EXPLANATION OF PLATES 46-53[578]. Complete List of Reference Letters. A. Anus. a. Dorso-lateral horn of white matter in brain. a.g. Accessory gland of male (modified accessory leg gland). at. Antenna. at.n. Antennary nerve. b. Ventro-lateral horn of white matter of brain. b.c. Body-cavity. bl. Blastopore. C. Cutis. c. Postero-dorsal lobe of white matter of brain. c.g. Supra-œsophageal ganglia. cl. Claw. c.m. Circular layer of muscles. co. Commissures between the ventral nerve-cords. co.2. Second commissure between the ventral nerve-cords. co1. 2. Mass of cells developed on second commissure. cor. Cornea. c.s.d. Common duct for the two salivary glands. cu. Cuticle. d. Ventral protuberance of brain. d.l.m. Dorsal longitudinal muscle of pharynx. d.n. Median dorsal nerve to integument from supra-œsophageal ganglia. d.o. Muscular bands passing from the ventro-lateral wall of the pharynx at the region of its opening into the buccal cavity. E. Eye. E. Central lobe of white matter of brain. e.n. Nerves passing outwards from the ventral cords. ep. Epidermis. ep.c. Epidermis cells. F.1, F.2, &c. First and second pair of feet, &c. f. Small accessory glandular tubes of the male generative apparatus. F.g. Ganglionic enlargement on ventral nerve-cord, from which a pair of nerves to foot pass off. f.gl. Accessory foot-gland. F.n. Nerves to feet. g.co. Commissures between the ventral nerve-cords containing ganglion cells. g.o. Generative orifice. H. Heart. h. Cells in lateral division of body-cavity. hy. Hypoblast. i.j. Inner jaw. j. Jaw. j.n. Nerves to jaws. L. Lips. l. Lens. l.b.c. Lateral compartment of body-cavity. le. Jaw lever (cuticular prolongation of inner jaw lying in a backwardly projecting diverticulum of the buccal cavity). l.m. Bands of longitudinal muscles. M. Buccal cavity. M1. Median backward diverticulum of mouth or common salivary duct which receives the salivary ducts. me. Mesenteron. mes. Mesoblastic somite. m.l. Muscles of jaw lever. m.s. Sheets of muscle passing round the side walls of pharynx to dorsal body-wall. od. Oviduct. œ. Œsophagus. œs.co. Œsophageal commissures. o.f.g. Orifice of duct of foot-gland. o.j. Outer jaw. op. Optic ganglion. op.n. Optic nerve. or.g. Ganglionic enlargements for oral papillæ. or.n. Nerves to oral papillæ. or.p. Oral papillæ. o.s. Orifice of duct of segmental organ. ov. Ovary. P. Pads on ventral side of foot. p. Common duct into which the vasa deferentia open. p.c. Posterior lobe of brain. p.d.c. Posterior commissure passing dorsal to rectum. p.f. Internal opening of nephridium into body-cavity. ph. Pharynx. pi. Pigment in outer ends of epidermic cells. pi.r. Retinal pigment. p.n. Nerves to feet. p.p. Primary papilla. pr. Prostate. R. Rectum. re. Retinal rods. R. m. Muscle of claw. s. Vesicle of nephridium. s1. Part of 4th or 5th nephridium which corresponds to vesicle of other nephridia. s.c.1. Region No. 1 of coiled tube of nephridium. s.c.2. Region No. 2 of ditto. s.c.3. Region No. 3 of ditto. s.c.4. Region No. 4 of ditto. s.d. Salivary duct. s.g. Salivary gland. sl.d. Reservoir of slime gland. sl.g. Tubules of slime gland. s.o.1, 2, 3, &c. Nephridia of 1st, 2nd, &c., feet. s.o.f.
  • 31. Terminal portion of nephridium. s.p. Secondary papilla. st. Stomach. st.e. Epithelium of stomach. sy. Sympathetic nerve running in muscles of tongue and pharynx. sy´. Origin of pharyngeal sympathetic nerves. T. Tongue. t. Teeth on tongue. te. Testis. tr. Tracheæ. tr.c. Cells found along the course of the tracheæ. tr.o. Tracheal stigma. tr.p. Tracheal pit. ut. Uterus. v.c. Ventral nerve cord. v.d. Vas deferens. v.g. Imperfect ganglia of ventral cord. Plate 46. Fig. 1. Peripatus capensis, x 4; viewed from the dorsal surface. (From a drawing by Miss Balfour.) Plate 47. Fig. 2. A left leg of Peripatus capensis, viewed from the ventral surface; x 30. (From a drawing by Miss Balfour.) Fig. 3. A right leg of Peripatus capensis, viewed from the front side. (From a drawing by Miss Balfour.) Fig. 4. The last left (17th) leg of a male Peripatus capensis, viewed from the ventral side to shew the papilla at the apex of which the accessory gland of the male, or enlarged crural gland, opens to the exterior. (From a drawing by Miss Balfour.) Prof. Balfour left a rough drawing (not reproduced) shewing the papilla, to which is appended the following note. “Figure shewing the accessory genital gland of male, which opens on the last pair of legs by a papilla on the ventral side. The papilla has got a slit-like aperture at its extremity.” Fig. 5. Ventral view of head and oral region of Peripatus capensis. (From a drawing by Miss Balfour.) Plate 48. Figs. 6 and 7 are from one drawing. Fig. 6. Peripatus capensis dissected so as to shew the alimentary canal, slime glands, and salivary glands; x 3. (From a drawing by Miss Balfour.) Fig. 7. The anterior end of Fig. 6 enlarged; x 6. (From a drawing by Miss Balfour.) The dissection is viewed from the ventral side, and the lips, L., have been cut through in the middle line behind and pulled outwards, so as to expose the jaws, j., which have been turned outwards, and the tongue, T., bearing a median row of chitinous teeth, which branches behind into two. The junction of the salivary ducts, s.d., and the opening of the median duct so formed into the buccal cavity is
  • 32. also shewn. The muscular pharynx, extending back into the space between the 1st and 2nd pairs of legs, is followed by a short tubular œsophagus. The latter opens into the large stomach with plicated walls, extending almost to the hind end of the animal. The stomach at its point of junction with the rectum presents an S-shaped ventro-dorsal curve. A. Anus. at. Antenna. F.1, F.2. First and second feet. j. Jaws. L. Lips. œ. Œsophagus. or.p. Oral papilla. ph. Pharynx. R. Rectum. s.d. Salivary duct. s.g. Salivary gland. sl.d. Slime reservoir. sl.g. Portion of tubules of slime gland. st. Stomach. T. Tongue in roof of mouth. Fig. 8. Peripatus capensis, x 4; male. (From a drawing by Miss Balfour.) Dissected so as to shew the nervous system, slime glands, ducts of the latter passing into the oral papilla, accessory glands opening on the last pair of legs (enlarged crural glands), and segmental organs, viewed from dorsal surface. The first three pairs of segmental organs consist only of the vesicle and duct leading to the exterior. The fourth and fifth pairs are larger than the succeeding, and open externally to the crural glands. The ventral nerve-cords unite behind dorsal to the rectum. A. Anus. a.g. Accessory generative gland, or enlarged crural gland of the 17th leg. at. Antenna. c.g. Supra-œsophageal ganglia with eyes. co. Commissures between the ventral nerve-cords. d.n. Large median nerve to dorsal integument from hinder part of brain. F.1, 2, &c. Feet. g.o. Generative orifice. œ. Œsophagus. œs.co. Œsophageal commissures. or.p. Oral papilla. p.d.c. Posterior dorsal commissure between the ventral nerve-cords. ph. Pharynx. p.n. Nerves to feet, one pair from each ganglionic enlargement. sl.d. Reservoir of slime gland. sl.g. Tubules of slime gland. s.o.1, 2, 3, &c. Segmental organs. v.c. Ventral nerve-cords. v.g. Imperfect ganglia of ventral cords. Figs. 9 and 10. Left jaw of Peripatus capensis (male), shewing reserve jaws. (From a drawing by Miss Balfour.) Fig. 9. Inner jaw. Fig. 10. Outer jaw. Plate 49. Figs. 11-16. A series of six transverse sections through the head of Peripatus capensis. Fig. 11. The section is taken immediately behind the junction of the supra- œsophageal ganglia, c.g., and passes through the buccal cavity, M., and jaws, o.j. and i.j.
  • 33. Fig. 12. The section is taken through the hinder part of the buccal cavity at the level of the opening of the mouth into the pharynx and behind the jaws. The cuticular rod-like continuation (le.) of the inner jaw lying in a backwardly directed pit of the buccal cavity is shewn; on the right hand side the section passes through the opening of this pit. Fig. 13. The section passes through the front part of the pharynx, and shews the opening into the latter of the median backward diverticulum of the mouth (M 1), which receives the salivary ducts. It also shews the commencement of the ventral nerve-cords, and the backwardly projecting lobes of the brain. Fig. 14. The section passes through the anterior part of the pharynx at the level of the second commissure (co.2), between the ventral nerve-trunks, and shews the mass of cells developed on this commissure, which is in contact with the epithelium of the backward continuation of the buccal cavity (M 1). Fig. 15. Section through the point of junction of the salivary ducts with the median oral diverticulum. Fig. 16. Section behind the pharynx through the œsophagus. b.c. Body-cavity. C. Cutis. c.b.c. Central compartment of body-cavity. c.g. Supra- œsophageal ganglia. c.m. Layer of circular muscles. co. Commissure between ventral nerve-cords. co. 2. Second commissure between the ventral nerve-cords. co1. 2. Mass of cells developed on second commissure (probably sensory). c.s.d. Common duct for the two salivary glands. d.l.m. Dorsal longitudinal muscles of pharynx. d.o. Muscles serving to dilate the opening of the pharynx. Ep. Epidermis. e.n. Nerve passing outwards from ventral nerve-cord. H. Heart. i.j. Inner jaw. j.p. Jaw papillæ. L. Lips of buccal cavity. l.b.c. Lateral compartment of body-cavity. le. Rod-like cuticular continuation of inner jaw, lying in a pit of the buccal cavity. l.m. Bands of longitudinal muscles. M. Buccal cavity. M 1. Median backward continuation of buccal cavity. m.l. Muscles of jaw lever. m.s. Muscular sheets passing from side walls of pharynx to dorsal body-wall. œ. Œsophagus. œs.co. Œsophageal commissures. o.j. Outer jaw. ph. Pharynx. s.d. Salivary duct. s.g. Salivary gland. sl.d. Reservoir of slime gland. sy. Sympathetic nerves running in muscles of tongue or pharynx. sy1. Origin of sympathetic nerves to pharynx. T. Tongue. v.c. Ventral nerve-cords. Figs. 17, 18. Two longitudinal horizontal sections through the head of Peripatus capensis. Fig. 17 is the most ventral. They are both taken ventral to the cerebral ganglia. In Fig. 17 dorsal tracheal pits are shewn with tracheæ passing off from them. (Zeiss a a, Hartnack's camera.) C. Cutis. c.s.d. Common salivary duct. ep. Epidermis. i.j. Inner jaw. M. Buccal cavity. M 1. Median backward diverticulum of
  • 34. mouth. o.j. Outer jaw. s.d. Salivary ducts. T. Tongue. t. Teeth on tongue. tr. Tracheæ. tr.p. Tracheal pits. Plate 50. Fig. 19. "A, B, C, D, E, F, G." Seven transverse sections illustrating the structure of the supra-œsophageal ganglia. (Zeiss A, Hartnack's camera.) a. Dorso-lateral horn of white matter. b. Ventro-lateral horn of white matter. c. Postero-dorsal lobe of white matter. d. Ventral protuberance of brain. e. Central lobe of white matter. o.p. Optic ganglion. “A. Section through anterior portions of ganglia close to the origin of the antennary nerve. B. Section a little in front of the point where the two ganglia unite. C. Section close to anterior junction of two ganglia. D. Section through origin of optic nerve on the right side. E. Section shewing origin of the optic nerve on the left side. F. Section through the dorso-median lobe of white matter. G. Section near the termination of the dorsal tongue of ganglion cells.” Plate 51. Fig. 20. Portion of a transverse section through the hinder part of Peripatus capensis (male). The section passes through a leg, and shews the opening of the segmental organ (o.s.), and of a crural gland, o.f.g., and the forward continuation of the enlarged crural gland of the 17th leg (f.gl.). (Zeiss a a, Hartnack's camera.) a.g. accessory gland of male (modified crural gland of last leg). C. Cutis. cl. Claw. cu. Cuticle. ep. Epidermis. f.gl. Crural gland. h. Cells in lateral compartment of body-cavity. o.f.g. Orifice of accessory foot gland. o.s. Opening of segmental organ. P. Three spinous pads on ventral surface of foot. pr. Prostate. R.M. Retractor muscle of claw. s. Vesicle of nephridium. s.c.i. Region No. 1 of coiled part of nephridium. sl.g. Tubule of slime gland. s.o.t. Terminal portion of nephridium. st. Stomach. st.e. Epithelium of stomach. v.c. Ventral nerve-cord. v.d. Vas deferens. Fig. 21. “Longitudinal vertical section through the supra-œsophageal ganglion and œsophageal commissures of Peripatus capensis. (Zeiss a a, Hartnack.)” at. Antenna. e. Central lobe of white matter. j. Part of jaw. s.g. Salivary gland. Fig. 22: drawn by Miss Balfour. Brain and anterior part of the ventral nerve-cords of Peripatus capensis enlarged and viewed from the ventral surface. The paired appendages (d) of the ventral surface of the brain are seen, and the pair of sympathetic nerves (sy1) arising from the ventral surface of the hinder part. From the commencement of the œsophageal commissures (œs.co.) pass off on each side a pair of nerves to the jaws (j.n.).
  • 35. The three anterior commissures between the ventral nerve-cords are placed close together; immediately behind them the nerve-cords are swollen, to form the ganglionic enlargements from which pass off to the oral papillæ a pair of large nerves on each side (or.n.). Behind this the cords present a series of enlargements, one pair for each pair of feet, from which a pair of large nerves pass off on each side to the feet (p.n). at.n. Antennary nerves. co. Commissures between ventral cords. d. Ventral appendages of brain. E. Eye. e.n. Nerves passing outwards from ventral cord. F.g. Ganglionic enlargements from which nerves to feet pass off. j.n. Nerves to jaws. or.g. Ganglionic enlargement from which nerves to oral papillæ pass off. or.n. Nerves to oral papillæ. p.c. Posterior lobe of brain. p.n. Nerves to feet. s.y. Sympathetic nerves. Fig. 23. “Longitudinal horizontal section through the head of Peripatus capensis, shewing the structure of the brain, the antennary and optic nerves, &c. (Zeiss a a, Hartnack's camera.)” at. Antenna. at.n. Antennary nerve. cor. Cornea. e. Central mass of white matter. l. Lens. op.n. Optic nerve. ph. Pharynx. p.p. Primary papilla covered with secondary papillæ and terminating in a long spine. sy. Pharyngeal sympathetic nerves. Fig. 24. “Eye of Peripatus capensis, as shewn in a longitudinal horizontal section through the head. The figure is so far diagrammatic that the lens is represented as filling up the whole space between the rods and the cornea. In the actual section there is a considerable space between the parts, but this space is probably artificial, being in part caused by the shrinkage of the lens and in part by the action of the razor. (Zeiss C, Hartnack's camera.)” (It appears that the ganglionic region of the eye is covered by a thin capsule, which is omitted in the figure.) cor. Cornea. l. Lens. op. Optic ganglion. op.n. Optic nerve. pi.r. Pigment. Re. rods. s.p. Secondary papillæ. Fig. 25. Longitudinal horizontal section through the dorsal skin, shewing the peculiar arrangement of the circular muscular fibres. (Zeiss A, Hartnack's camera.) Plate 52. Fig. 26. Portion of ventral cord of Peripatus capensis enlarged, shewing two ganglionic enlargements and the origin of the nerves and commissures. (From a drawing by Miss Balfour.) co. Commissures. E.n. Nerves passing out from ventral cords. F.n. Nerves to feet. g.co. Commissures between the ventral cords containing ganglion cells. v.g. Ganglionic enlargements.
  • 36. Fig. 27. Segmental organ from the 5th pair of legs of Peripatus capensis. This nephridium resembles those of the 4th legs, and differs from all the others in its large size and in the absence of any dilatation giving rise to a collecting vesicle on its external portion (enlarged). The terminal portion has the same histological characters as in the case of the hinder segmental organs. (From a drawing by Miss Balfour.) Fig. 28. Segmental organ or nephridium from the 9th pair of legs of Peripatus capensis, shewing the external opening, the vesicle, the coiled portion and the terminal portion with internal opening (enlarged). (From a drawing by Miss Balfour.) o.s. External opening of segmental organ. p.f. Internal opening of nephridium into the body-cavity (lateral compartment). s. Vesicle of segmental organ. s1. Portion of segmental organ of 4th and 5th legs, corresponding to vesicle of the other nephridia. s.c.1. First or external portion of coiled tube of nephridium, lined by columnar epithelium with small nuclei; the cells project for very different distances, giving the inner boundary of this region a ragged appearance. s.c.2. Region No. 2 of coiled tube of nephridium, lined by small closely-packed columnar cells. s.c.3. Region No. 3 of coiled tube of segmental organ, lined by large flat cells with large disc-shaped nuclei. s.c.4. Region No. 4 of coiled tube of nephridium; this region is very short and lined by small columnar cells. s.o.t. Terminal portion of nephridium. Fig. 29. “Portion of nephridium of the hindermost leg of Peripatus capensis, seen in longitudinal and vertical section. The figure is given to shew the peritoneal funnel of the nephridium. Portions of the collecting sack (s.) and other parts are also represented. (Zeiss B, Hartnack's camera.)” p.f. Peritoneal funnel. s. Vesicle. s.c.1, s.c.2, s.c.3. Portions of coiled tube. Fig. 30. “Section through a tracheal pit and diverging bundles of tracheal tubes” taken transversely to the long axis of the body. (Zeiss E, oc. 2.) (From a rough drawing by Prof. Balfour.) tr. Tracheæ, shewing rudimentary spiral fibre. tr.c. Cells resembling those lining the tracheal pits, which occur at intervals along the course of the tracheæ. tr.s. Tracheal stigma. tr.p. Tracheal pit. Fig. 31. “Sense organs and nerves attached from antenna of Peripatus capensis (Zeiss, immersion 2, oc. 2.)” (From a rough drawing by Prof. Balfour.) The figure shews the arrangement of the epidermis cells round the base of the spine. The spine is seen to be continuous with the inner layer of the cuticle.
  • 37. Fig. 32. Section through the skin of Peripatus capensis; it shews the secondary papillæ covered with minute spinous tubercles and the relation of the epidermis to them. (The cuticle in the process of cutting has been torn away from the subjacent cells.) The cells of the epidermis are provided with large oval nuclei, and there is a deposit of pigment in the outer ends of the cells. The granules in the protoplasm of the inner ends of the cells are arranged in lines, so as to give a streaked appearance. (Zeiss E, oc. 2.) (From a rough drawing by Prof. Balfour.) c. Dermis. cu. Cuticle. ep.c. Epidermis cells. pi. Deposit of pigment in outer ends of epidermis cells. s.p. Secondary papillæ. Fig. 33. Female generative organs of Peripatus capensis, × 5. (From a rough drawing by Prof. Balfour.) The following note was appended to this drawing: “Ovary rather to dorsal side, lying in a central compartment of body-cavity and attached to one of the longitudinal septa, dividing this from the lateral compartment between the penultimate pair of legs and that next in front. The oviducts cross before opening to the exterior, the right oviduct passing under the rectum and the left over it. They meet by opening into a common vestibule, which in its turn opens below the anus. On each side of it are a pair of short papillæ (aborted feet?).” F. 16, 17. Last two pairs of legs. od. Oviduct. ov. Ovary. ut. Uterus. v.c. Nerve-cord. Plate 53. Figs. 34-39. Five young embryos of Peripatus capensis; ventral view. All, excepting Fig. 37, from drawings by Miss Balfour. In figures 34 to 38a denotes what is probably the anterior extremity. Fig. 34, Stage A. Youngest embryo found, with slightly elongated blastopore. Fig. 35, Stage B. Embryo with three mesoblastic somites and elongated blastopore. The external boundaries of the somites are not distinct. Fig. 36, Stage C. Embryo with five somites. The blastopore is closing in its middle portion. Fig. 37, Stage D. The blastopore has completely closed in its middle portion, and given rise to two openings, the future mouth and anus. (From a rough drawing left by Professor Balfour.) (Zeiss A, Camera Oberhaus. on level of stage.) The following note was appended to this drawing in his handwriting: “Young larva of Peripatus capensis. I could not tell for certain which was the anterior end. Length, 1.34 mm.”
  • 38. Fig. 38, Stage E. Embryo with about thirteen mesoblastic somites in which the flexure of the hind part of the body has commenced. The remains of the original blastopore are present as the mouth, placed between the second pair of mesoblastic somites, and the anus placed on the concavity of the commencing flexure of the hind part of the body. Fig. 39. Side view of same embryo. Figs. 40-42. Drawings by Professor Balfour of three transverse sections through the embryo from which fig. 36 was taken. (Zeiss c, Camera.) Figs. 40 and 42 pass through the region of the blastopore. bl. Blastopore. ep. Epiblast. hy. Hypoblast. me. Mesenteron. mes. Mesoblastic somite. Fig. 43. Male generative organs of Peripatus capensis, viewed from the dorsal surface. (From a drawing by Miss Balfour.) a.g. Enlarged crural glands of last pair of legs. F.16, 17. Last pairs of legs. f. Small accessory glandular tubes. p. Common duct into which vasa deferentia open. p.r. Prostate. te. Testes. v.c. Nerve-cord. v.d. Vas deferens. [572] Comparative Embryology; original edition, Vol. I. p. 318. [This edition, Vol. II. p. 385.] [573] We have seen nothing in any of our sections which we can identify as of so-called mesenchymatous origin. [574] This edition, Vol. II. p. 457. [575] This edition, Vol. III. p. 352. [576] This edition, Vol. III. p. 356. [577] This edition, Vol. III. pp. 378, 379. [578] The explanations of the figures printed within inverted commas are by Professor Balfour, the rest are by the Editors. CAMBRIDGE: PRINTED BY C. J. CLAY, M.A., AND SON, AT THE UNIVERSITY PRESS.
  • 39. TRANSCRIBER'S NOTES: Hyphens were spaced in ranges of small numbers to ease readability, e.g., “1/2000-1/3000 of an inch” was changed to “1/2000 - 1/3000 of an inch”. Raised dots in numbers were converted to decimals. Use of periods and commas in the abbreviations within and referring to figures and plates is inconsistent. Often, punctuation marks do not match the illustrations to which they refer. Periods were retained; commas were added to separate figure numbers from abbreviations within the figure. Spacing within the abbreviations was standardized. Footnotes were renumbered sequentially, and were moved to the end of the chapter. There is no anchor for footnote 496; anchor was placed at the spot the transcriber deemed it likely belonged. Footnote 351 incorrectly identifies the page number of the article on urinogential organs of vertebrates. The number provided in the original text of the footnote was retained, but the link was corrected. Changes for consistency within the text of the book: body cavity to body-cavity body wall to body-wall choroid-slit to choroid slit develope(s) to develop(s)
  • 40. dog fish to dog-fish Elasmobranchs to Elasmobranchii Entwickelung to Entwicklung head-fold to head fold inter-renal to interrenal juxta-position to juxtaposition lenslike to lens-like re-agent(s) to reagent(s) omphalo-meseraic to omphalomeseraic pleuroperitoneal to pleuro-peritoneal proto-vertebra(æ) to protovertebra(æ) re-appear to reappear semi-lunar to semilunar side-fold to side fold spongework to sponge-work subgerminal to sub-germinal sub-intestinal to subintestinal sub-kingdom to subkingdom sub-notochordal to subnotochordal suboesophageal to sub-oesophageal supraoesophageal to supra-oesophageal urino-genital to urinogenital Urogenital-system to Urogenitalsystem, except where cited as a title of a work. Verwandschaft to Verwandtschaft widespread to wide-spread wood-cut(s) to woodcut(s) zool. zoot. to zool.-zoot. italics removed from eight instances of “vide” italics, where missing, were added to loc. cit., i.e. and e.g. Other changes: [TN1] changed from 'reremainder' [TN2] changed from 'on' [TN3] changed from 'splachnopleure'
  • 41. [TN4] changed from 'Sitzen.' [TN5] changed from 'diffiulty' [TN6] changed from 'it' [TN7] changed from 'primive' [TN8] and [TN10] changed from 'opthalmicus' [TN9] Figure number is missing in the original. [TN11] changed from 'Ureierernester' [TN12] changed from 'vascula' [TN13] changed from 'Metozoa' [TN14] duplicate word 'of' removed [TN15] changed from 'protodæum' [TN16] changed from 'is it' [TN17] changed from 'is is' [TN18] changed from 'continous' [TN19] changed from 'Zussammenhang' [TN20] changed from 'Tranverse' [TN21] changed from 'odontophor' [TN22] changed from 'lens' [TN23] changed from 'Platyelminthes'
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