Harvard University. Museum of Comparative Zoology..

Contributions from the Zoölogical Laboratory of the Museum of ..., Issues 21-30 online

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.RKER. — Compound Eyes In Crostaceans.

PLATE V.

Porcellio,

g. 46. A transverse section through a retinula in a plane slightly distal to
basement membrane. The single, light, central spot represents
proximal end of the rhabdome. X 475.

Idotea robusta, Kroyer.

(Figs. 47, 48.)

g. 47. A transverse section through the distal end of a retinula. The bod
one of which is marked ar, are splieres of coagulated material wl]
occur in the interommatidial spaces, and which have been brou
into prominence by the action of the hardening reagent X 47&
48. A transverse section through three ommatidia in the region of tl
rhabdomes. X 475.

Idotea trrorata, M. Edws.
(Figs. 49-57.)

g. 49. The anterior face of a section transverse to the chief axis of the bo
and passing through the eye on the right side of the head. X 14

50. A longitudinal section of an omraatidium. The numbers at the lef

the figure correspond to the numbers of the following six figu
of transverse sections and mark the levels at which the latter w
taken. X 475.

51. A transverse section through the distal ends of the cones. X 475i

52. A transverse section through the middle region of a cone. X 475.

53. A transverse section through the middle of a retinula. Near the cei

of each cell can be seen a small axis of nerve fibrillse. X 475.

54. A transverse section through a retinula composed of seven cells insti

of six. This section was cut approximately at the same level as t
shown in the preceding figure. X 475.

55. A transverse section through a retinula near its proximal end. Ei

fibrillar axis is much larger at this plane than in that shown in I
ure 58- X 476.

50. A transverse section of several groups of retinular cells immediat
proximal to the basement membrane. X 475.

57. A transverse section of four retinular cells at the level in which tli
nuclei occur. The axis of nerve fibrillse in the plane of this sect
and in that of the preceding one (Fig. 56) are smaller than tl
are at the base of the retina (compare Fig. 55).

SphcBToma.
(Figs. 58, 59.)
I. 58. A transverse section of a retinula at a level slightly distal to the bs
ment membrane. X 475.
50. A transverse section of the fibrous ends of the cells from a single
tinula. The plane of section is slightly proximal to the basemi
membrane. The only indication of an axis of nerve fibrillse Is i
more transparent condition of the central part of the cells, due to '
partial absence of pigment granules. X 475.



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Parker. — impound Eyes in Crustaceans.



PLATE VL

Serdls.

Figures 60 to 64 incIuBive represent the structure of the ommatidium it
adult. Figures 65 to 72 are drawn from sections of ommatidia in we
▼anced embryos. All figures are magnified 476 diameters.

Fig. 60. A tangential section through the most distal portion of the retina,
section includes a portion of a cone and the tissue lying betwe
and two adjoining cones.

" 61. A transverse section of a retinula in the region of its rhabdome.
arrangement of the pigment granules and nerre fibrillae is indi(
in only one of the four cells. Of the two lines which appei
separate the cone cells (d. con.) from the rhabdomere (rhh*m.]
one nearer the axis of the ommatidium is the real line of se]
tion ; the other lies within the substance of the rhabdomere
(compare p. 92).

" 62. A transverse section through a retinula proximal to the rhabdome
in the region of the hjaline cell. As in Figure 61, the pig
granules are drawn in only one of the retinular cells.

'' 68. A transverse section through a single retinular cell in the region <
nucleus. The axis of nerve fibrillae is represented by several i
axes in the substance of the cell at one side of the nucleus.

" 64. A transverse section of the fibrous ends of the cells of one retinu
their passage through the aperture in the basement memb
Each cell shows a well marked fibrillar axis, the centre of whi
often occupied by* a core of pigment. The basement membra
viewed from its distal face. The irregularly oval body in the i
left-hand corner of the figure is probably a nucleus. It lies oi
proximal face of the membrane through which it is seen.

" 65. A longitudinal section through the ommatidium of an advanced eml
The numbers at the left of the figure correspond to the numbc
the six following figures of transverse sections, and indicate
levels at which the latter were taken. Figure 68 represents a
tion so nearly in the same plane as that shown in Figure 67 th;
number has been omitted.

" 66. A transverse section at the level of the corneal hy podermis.

" 67. A transverse section through the distal end of a cone.

" 68. A transverse section made in a plane only slightly proximal to
shown in Figure 67.

" 69. A transverse section through the region of the distal retinular nuclc

" 70. A transverse section through the proximal ends of the cones.

" 71. A transverse section through the retinula in the region of the rhabd

" 72. A transverse section at the level of the proximal retinular nuclei.



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LKEB. — Compoond Eyes in Cnutaceans.



PLATE VIT.

Mytis.

. 73. A longitudinal section of an ommatidium. The numbera at the I<
the figure indicate the leveU at which the sections fur Figures '
were taken. X 475.
74. Tlie distal face of a corneal facet, cleaned in potash and examin

water. X 476.
76. A transverse section of three ommatidia in the plane of the comes
podermis. X 475.

76. A transverse section through the distal end of a cone. X 475.

77. A transverse section through the proximal end of a cone and the ad

ing distal retinuUr cells. X 476. /

78. A transverse section similar to that shown in the preceding fl

except that it is depigmented and stained in Kleinenberg's i

hsematoxylin. X 475.
'igures 79 to 82 inclusive represent consecutive transverse sections througl
region of the proximal retinular nuclei of four adjacent ommatidia.
centre of each ommatidium is indicated by the group of cone cells (c/.
and the corresponding ommatidia in different sections are designated bj
same Roman numeral. The nuclei around ommatidium 11. have been i
bered in Figures 79-81. Figure 79 represents the most distal section
Figure 82 the most proximal one of the series.
. 79. The bodies marked x and y are portions of nuclei the rest of whici

correspondingly marked in Figure 80. X 475.

83. A transverse section of the four fibres at the dis.tal end of the rod (

pare p. 102). Depigmented, and stained in Kleinenberg's alum-1
atoxylin. X 615.

84. A transverse section of the rod at a slightly more proximiil level

that shown in Figure 83. Depigmented, and stained in Kleinenfa
alum-hsematoxylin. X 615.

85. A transverse section of tlie retinula somewhat distal to the distal

of the rhabdome (compare Fig. 90). Depigmented, and stain<
Kleinenberg's alum-hsematoxylin. X 615.

86. A transverse section from the region between the distal end of the i

dome and the proximal end of the rod (compare 86 in Fig. 90).
pigmented, and stained in Kleinenberg's alum-hsematoxylin. X

87. A transverse section through the rhabdome and surrounding retii

cells. X 616.

88. A transverse section, at the level of the basement membrane, thr

the nerve fibres from a single retinula. Depigmented, and sti
in Weigert's hsematoxylin. X 615.

89. A transverse section through the fibres of the optic nerve at a level

way between retina and optic ganglion. Preparation as in Fi
88. X615.

90. A longitudinal section through the basal portion of one and parts ol

adjoining ommatidia. Depigmented, and stained in Kleinenb
alum-hsematoxylin. X 616.

91. A section cut in the same plane as that shown in the previous fi

but including only the proximal ends of two rhabdomes. Pre
tion as in Figure 90. X 615.
02. A cone viewed from the side. Isolated in Miiller*8 fluid and studio
water. X 475.



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Parker. — Compound Eyes in Cnutaceaiis



PLATE Vin.

Gonodactiflus,

Fig. 93. Part of a tangential section through a superficial portion of the re
The extreme edges of the section both riglit and left are immedia
beneath the corneal cuticula ; the central portion is farthest from
cuticula. At the right of the middle line are seen the ends of
larger ommatidia ; at the left, those of the smaller. X 275.

" 94. A longitudinal section of a large ommatidium. The numbers at the
of the figure correspond to the numbers of six figures of transT
sections (Figs. 90-101), and mark the levels at which the latter i
made. Depigmented. X 275.

" 95. A longitudinal section of a small ommatidium containing its nat
pigment. X 275.

*^ 96. A transverse section through the cells of the corneal hypodermis and
distal end of the cone in a large ommatidium. X 275.

" 97. A transverse section through the distal part of a cone in a large om
tidium. X 275.

** 98. A transverse section through the middle of a cone from a large om
tidium. X 275. -

" 99. A tran verse section through a number of cones at the level of the di
retinular nuclei in the large ommatidia. X 275.

" 100. A transverse section through six retinulss of the large ommatidli
the region of the proximal nuclei. Each retinula is numbered,
plane of this section is slightly oblique, so that retinula 1 is cut
relatively higher level than any of the others, and retinula 6 at
lowest level. X 475.

" 101. A transverse section of a retinula from one of the larger ommatidia,
plane not far from the basement membrane. Depigmented. X

" 102. A transverse section of a retinula from one of the smaller ommatidia
in a plane nearly corresponding to that of Figure 101. X 475.



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Parker. — Compound Eyes in Crustaceans.



PLATE IX.

Palamonetes,
In all Figures on this plate the magnification is 476 diameters.
Fig. 108. A longitudinal section of an ommatidium. The numbers at the lef
the figure correspond to the numbers of nine of the follow mg
ures of transverse sections, and mark the levels at which tlie la
were taken.
*^ 104. A longitudinal section of an ommatidium which has been depigmen
The bodies marked x resulted from the action of the depigmem
reagent.
" 105. A fsicet from the corneal cuticula ; cleaned in strong potassic hydi

and examined from its distal side in water.
" 106. A transverse section through the region of the corneal hypodermis.
** 107. A transverse section through the distal end of a cone in the regio

the nuclei of the cone cells.
" 108. A transverse section through the middle of a cone.
" 109. A transverse section through parts of four ommatidia in the regie

the distal retinular nuclei.
Figures 110-112 represent three successive transverse sections, each thro
five ommatidia, in the region of their proximal retinular nuclei. Only
outlines of the nuclei and the five groups of cone cells (c/. con.) are drs
The nuclei in each ommatidium are numbered from 1 to 7, and as their ]
of arrangement is the same in the different ommatidia, corresponding ni:
have been designated by the same number. In some cases the nuclei i
cut in two, and consequently appear in two adjoining sections. In i
cases the two parts have been marked with the same number. Figure
is the most distal of the series; Figure 112, the most proximal.
Fig. 1 13. A transverse section of the retinula near the distal end of the rhabdc
Depigmented.
" 114. A transverse section of four retinulss at the level of the eighth retin

nucleus.
" 116. A transverse section through four retinulss in the region of the accesi
pigment cells; viewed by reflected light The retinuIsB appea:
dark masses embedded in a whitish field composed for the most
of the substance of the accessory pigment cells.
" 116. A transverse section through a retinula at about the same level as

shown in Figure 115. Depigmented.
" 117. A transverse section through the optic nerve fibres at a level slig
proximal to the basement membrane. Depigmented.



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PABKE&.— Compoand Eyes in CrustoceanB.

PLATE X.
In all Figures on this plate tlie magnification is 476 diameters.

Cambarus.
Figures 118-122 represent a series of five successive transverse sections tlirougli
and parts of four adjoining omroatidia in the region of their prox
retinular nuclei. Figure 118 represents the most distal sectic
the series^ Figure 122, the most proximal. In these figures,
the outlines of the nuclei and the groups of cone cells are drawn

Crangon.
Fig. 128. A transverse section through a number of ommatidia in the regi(
their distal retinular nuclei.

Palmurus.

Fig. 124. A transverse section through a retinula in its middle region. The
lines of the retinular cells cannot be distinguished ; the positic
each cell is marked by an irregular light mass in its centre.
'* 125. A transverse section through a retinula in the plane of its ei
nucleus. Depigmented.

Cancer.

(Figs. 126-131.)

Fig. 126. A corneal facet viewed from its distal surface. The cuticula from ^
this facet was drawn was cleaned by being boiled m a strong aqu
solution of potassic hydrate. It was examined in water.

*' 127. A transverse section of the distal end of a cone.

" 128. A transverse section through three ommatidia at the level of the c
retinular nuclei. The pigment granules have been indicated in
the lower circle of cells.

'* 129. A transverse section through the distal region of four retinulae. Ir
two on the right, the pigment g^nules have not been drawn

" ISO. A transverse section through a retinula near the base of the retina.

" 131. A slightly oblique section through the basement membrane. The u
part of the figure represents the retinulae as seen m transverse
tion distal to the basement membrane; the part marked mb
represents the region in which the membrane itself appears m sec
and the lower half of the figure shows the cut fibres of the (
nerve. The pigment granules are omitted from the right side o
figure. The transition from the retinular cells to the nerve t
is evident in passing over the section from top to bottom.



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tvpJL



Bulletin of the MuBenm of Gomparatiye Zoology,

AT HARVARD COLLEGE.

Vol. XXI. No. 3.



2i



ON SOME POINTS IN THE ANATOMY AND HISTOLOGY
OF SIPUNCULUS NUDUS, L.



Bt Hbnrt B. Ward.



With Three Plates.



4

^'CAMBRIDGE, U.S.A.:
PRINTED FOR THE MUSEUM.
May, 1891.



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No. 3. — On some Paints in the Anatomy and Histology of
Sipuncultis nudus, L. By Henry B. Ward.^



COKTBNTS.



I iDtroduction 143

Method* 144

II. External Anatomy .... 146

1. Introrert 146

2. TeDUcalar Fold .... 147

Histology 149

1. Body WaU 149

a. Caticola and Hypodermii 149

6. Catis 160

c Pigment CeiU .... 160

d. TUkrmsd RndiM .... \liSt



III



2. Tentacular Fold . .

a. Oral WaU . . .

b. Migratory Corpuscles

c. Musculature. . .

d. Vascular System .

e. Aboral WaU . . .

3. Nerrous System . .
a. Brain

a. Ganglionic Cells
p. Internal Structure
&. r!»rphnLl Nerves >



Pass
169
169
160
161
162
164
ite
166
166
169
170



tuseum of Comparattbt ^oolosi;, Cambribge, ^ass.

tVz^A the compliments of

Alexander Agassiz.



the Cultusministerium of Baden, was embraced to procure new, carefully
preserved material. A study of the literature on Sipunculus revealed
such lack of agreement between authors that a more general study
of the form seemed likely to yield results, and, on the advice of Prof.

1 Contributions from the Zoological Laboratory of the Museum of Comparative
Zoology, under the direction of £. L. Mark, No. XXVI
VOL. XXI. — xo. 3.



k



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No. 3. — On some Paints in the Anatomy and Histology of
Sipunculvs nudus, L. By Henry B. Ward.^



COKTBim.
Pao



III.



I iDtrodaction 143

Method* 144

IL External Anatomy .... 146

1. IntroTert 146

2. TeDtacular Fold .... 147

HiBtology 149

1. Body WaU 149

a. Coticala and HypodennU 149
160
160
162
162
166
167
169



b. Cutis

e. Pigment Cells . . .

d. Dermal Bodies . . .
a. Bicellnlar Glands .
p. Multicellalar Glands
y. Sense Papilla . .

e. Muscular Layers . .



Pass

2. Tentacular Fold .... 169

a. Oral WaU 169

b. Migratory Corpuscles . 100

c. Musculature 161

d. Vascular System ... 162

e. Aboral WaU 164

8. Nerrous System .... 1^6

a. Brain 166

a. Ganglionic CeUs . . 166

p. Internal Structure . . 109

6. Cerebral Nerres ... 170
c. Ventral Nerre Cord and

Plexi 171

4. Cerebral Organ .... 172

IV. Conclusions 176



Bibl]<^niphy 180 | Explanation of Figures



183



I, Introduotion.

SoMi two years ago, while working on Sipiinculus nudus in the zoo-
logical laboratory at Gdttingen under Prof. £. Ehlers, my attention was
attracted by a peculiar organ in the region of the dorsal ganglion ; and
although it was a prominent feature of aU transverse sections, no men-
tion of its presence was found in the literature on Sipunculus. The ob-
servations made at that time interested me so much that the opportunity
afforded by a short stay at the Naples Zoological Station last spring,
for which I am indebted to the great kindness of Prof. A. Weismann and
the Cultusministerium of Baden, was embraced to procure new, carefully
preserved material. A study of the literature on Sipunculus revealed
such lack of agreement between authors that a more general study
of the form seemed likely to yield results, and, on the advice of Prof.

1 Contributions from the Zoological Laboratory of the Museum of Comparative
Zoology, under the direction of £. L. Mark, No. XXVI
VOL. XXI. ~ xo. 3.



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BULLETIN OF THE

1 Mark, a more particular consideration of some moot anatomies
histological points was undertaken. This was unfortunately limite<
:he material on hand, which consisted merely of the anterior portioi
he body, corresponding in general to the introvert of recent writers
this contains, however; nearly all of the important organs of th<
irons system to which especial attention has been paid in this papei
as its separation from the rest of the body at the time of killin]
ired good preservation, it is hoped that the conclusions reached ma;
be without value, in spite of their incompleteness. The histologica
icture of the body wall and of the nervous system has been treate(
letail, and from the results an attempt has been made to throw som
' light on the systematic position of the Sipunculids.

Methods.
'he material used in these investigations was preserved with especia
), and every effort was made to procure a method of killing whicl
aid afford a clear idea of anatomical and histological relations unde
oaal conditions, since many of the contradictory statements of va
IS writers have been undoubtedly the result of studying specimen
a distorted state, due to muscular contraction, or have followe*

examination of tissties poorly preserved. The thick impermeabl
icula, and the wealth of muscular tissue in the body wall, render it
Lcult matter to avoid at the same time both evils. The metho<
lly adopted as yielding the best results is as follows.
Lftor remaining some time in clean sea-water to clear tentacles, bod;
I, and oesophagus of adhering sand, the animals were brought int
lallow dish of sea-water, and 5 ^ alcohol was allowed to flow gentl
r the surface, forming thus a thin film, which disseminated itse]
[lually, and produced in the animals a complete relaxation of th
y muscles. It did not seem to answer equally well when the alcohc

water were mixed at the start, as has been recommended for som
nals. The length of time necessary for the attainment of cone
:e narcosis cannot be exactly given. It varies greatly with differen
ividiials ; but if, after lying some four to eight hours, the animals mak
contractions on being gently probed with a dull instrument, they ma
regarded as sufficiently stupefied, and transferred to 50 5^ alcoho!
er a short stay in this, the introvert was cut off, and this alone sul
ed to treatment with higher grades of alcohol, which insured the pen<
:ion and consequent good preservation of the tissues. The only poin
the process which requires especial care, and which often produce



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MUSEUM OF COMPARATIVE ZOOLOGY. 145

a disappointing failnre^ is the transfer from the salt water and its added
alcohol to 50^ alcohol. If the animal is but partially narcotized, the
muscular contraction induced by the transfer will spoil the specimen.
If, OQ the other hand, it be left too long^ the weaker parts of the body
wall, especially the upper smooth zone of the introvert, swell out quite
rapidly (through osmosis )), and not only the external form but the his-
tological elements as well are badly distorted. The golden mean be-
tween these two extremes yields specimens as excellent for histological
work as for the study of external relations. Material preserved in this
way may be well stained by all methods. Where any stain has been
of especial value in the study of particular organs or tissues, it will be
noted under the topic in question. lu this place I wish to express my
thanks to Profc R Eblers of Gdttingen and to Prof. A. Dohm of Naples
for past flavors, and to Mr. A. Agassis, Prof. K L. Mark, and Prof. K B.
Wilson for more recent kindnesses in supplying me with material for
this study.

n. External Anatomy.

Selenka ^83, p. 92) has given a full description of the external char-
acters of Sipunadus nudus. There are however numerous points of in-
terest which first appear in a well expanded specimen, and which deserve
especial attention. The body consists of a large posterior region covered
by the quadratic integumentary areas (Hautfelder) and of a portion
anterior to these, which is called the introvert.

1. Introvert.

This includes on the average one sixth of the entire length of the
animal, and has in general the shape of a truncated cone (Fig. 1), the
anterior base of which, only a little less in diameter than the posterior,
is surmounted by a wreath of tentacles which nearly encircle the mouth.
This region is ordinarily found entirely, or for at least two thirds of its
length, invaginated into the following portion of the body, and is only
rarely seen extended. In the latter condition it measures from three to



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