Full resolution (JPEG) - On this page / på denna sida - Sidor ...
<< prev. page << föreg. sida << >> nästa sida >> next page >>
Below is the raw OCR text
from the above scanned image.
Do you see an error? Proofread the page now!
Här nedan syns maskintolkade texten från faksimilbilden ovan.
Ser du något fel? Korrekturläs sidan nu!
This page has never been proofread. / Denna sida har aldrig korrekturlästs.
Since executing the drawings for the preceding plates, I have met with an accident which has disabled my right arm and prevented me executing the drawing,
for this plate with su much exactitude as I desired.
Fie I Jf atoa* iilk fons» AA Oc I Cam.-luc Transverse section through the middle of the body; the section has passed through the third parappdium and
vesicula seminalis on one side, and ’through ’a segmental glandulous sack ..«.«.> on the other side. b.C. Ventrg nerve-cord^ lem., Inn. Longitudinal commissures. ,„„. Stomach, tin.
In-tcslinalbranehcs , t. Testes which are seen, in several places, extending ... the ectoderm of the dorsum, ovov. Ova dv. Dorso-ventral muscles Mr. Musculus-ceutrnhs. p.l. Musculus
nr "actor Urn«,. /. Chief hook. t.h. Supporting rod. h.k. Hook-gland. t ’J- Parapodial ganglion «. The fibrillar prolongation passing from the gangbor, m o the parapodii.m
pi OJLIOI t’ 2 4 2a 1/ aruffi n *p iZeiss K. Oi 2. Arbitrary magnification.) Iransverse section (fig. J) and horizontal section (fig. ia.) of the neurilcminn-
shcath of the dorsal side of the ventral nerve-cord! showing the peculiar structure (vide pp. 27 and 72 In fig- 2, this structure is only present in the middle, whilst the portions e.t.
,,r the sheath at both ends of the figure, are almost homogeneous on the inner side. ,, . ,
01 tiu sne. il, Horizontal section of the ventral ncrve-cord illustrating, schematically, the two different types of ganglionic cells and nervous tube- vide pp. 30, 34
» „. Thc ..K „’j,h a prolongation forming, directly, a nervous tube are indicated by the letter <•., and the cells with a prolongation which becomes loosened out into
the fibrillar reticulation are Indicated by the letter r. r’. I’air of large cells (referred to at pp. iS. .9 and 72). Smaller cells situated in the mUldlc of the cor,I, their prolong,
li s firitiiric chiasina r 1 -ml r’ Cells that send their prolongations, through the commissures, into a peripheric nerve of the same side. «.». Cells, situated at the margin of
,T »Jural cord which send their prolongations, through a transverse commissure, into a peripheric nerve of the opposite side of the ventral coril. «.•’. Tells, situated at the root
, lhll ’w|,ich scn<| their prolongations directly into the nerve. e.*\ A multipolar cell in similar situation to c.", r Gangrømc cells, whose prolongations become loosened
into the’fibrillar reticulation of the longitudinal commissure situated 0,1 same side as they themselves are. r-. Cells, whose prolongations become loosened out into the lihrillar
°t lotion of the opposite side l’.’. Cell, whose prolongation passes to the longitudinal nervous tubes (it) of the opposite longitudinal commissures. 1 Nervous tubes originating
Jf ’,h fibH„nr reticulation of the longitmlinal commissure of the same side 2. Nervous tubes originating in the fibrillar reticulation of the opposite longitudinal commissure.
Nervous nibes originating in the longitudiual nervous tubes (l.t.) of the longitudinal commissure of the same side. 4. Nervous tubes originating in the longitudinal tubes ,,( the
opposite longitu.linal commissure t.l Bundle of longitudinal nervous tubes running along the inner dorsal side of each longitudinal commissure l.t.’ Smaller bundle of longitudinal
nervous tubes running along the outer side of each longitudinal commissure
Fig 4. M. giganteum, 11 sji. Ideal, transverse section of the ventral nerve-cord, illustrating the two different types of ganglionic cells and nervous lubes mil
showing the cuurse of the cell prolongations. The section has passed, on one side, through the root of h large nerve {n.st.): in the middle, it has passed along one side of a Inrgi
transverse commissure; anil ..11 the other side, it lias passed between two nerves, As in fig. 3, the cells whose prolongations, directly, form a nervous tube arc indicated by the
letter . and the cells’whose prolongations become loosened out into the fibrillar reticulation are indicated by the letter r. The nervous tubes arc indicated by numerals, r.’. Mesial
cells corresponding to r ’, fig. 3 whose prolongations traverse each other, and pass through the longitudinal commissure into peripheric nerves on each side. C’1. Cells, situated in
groups "(corresponding to i\> and ’ ’ in fig 31 >••I iroups of cell- corresponding to r.» in fig. 3I whose prolongations pass, through the transverse commissure, into nerves of the opposite
side, i’ ’ . < ;roup- of cells sending their prolongations directly into the nerve at the root of which they are situated, r. V Isolated eel! that sends its prolongation, through the transverse commissure,
into the large nerve of the opposite side r ’. Large cells whose prolongations become, immediately. loosened out into the fibrillar reticulation. > .’. Cells, with spreading reticulated prolongations,
situated below the extremities of the transverse commissure, and pertaining to the same group cf cells as c.2. r.-’. Small cells, with reticulated prolongations situated ..11 the inferior side of of
tlu-longitudinal commissure. r.K Cell whose prolongation passes, a short distance, into the fibrillar mass previous to becoming loosened out vide fig 6 d). r.*. Small cells, situated under the root of
the large nerve (vide lig.^6 a), r " and »•.’ Small cells situated in the fibrillar mass; i’." has two reticulated prolongations (vide also tig. 6 b), /’.’ is multipolar 1 vide fig. 6 c’’. 1. Roots of nervous
tubes, corresponding to those indicated by same numeral in fig. 3. 2. Roots of nervous tubes (corresponding to numeral 3 in fig. 31 originating amongst the longitudinal nervous tubes of the
longitudinal commissure of the same side 3. Root of nervous tubes, corresponding to numeral 2 in fig. 5. l.t Trans-sected bundles of longitudinal nervous tubes of the longitudinal
commissure. n.t bundle of nervous tubes passing to a peripheric nerve. «’.». Intermediate nerve, from which a branchlet passes to one of the longitudinal commissures. The fibrils of
this branchlet issue, oue from each tube of tlu intermediate nerve (vide also fig. 14 in which a similar branchlet is illustrated), n.sk. Outer ncurilenuna-shcath, 1 nsk Inner neurilemma-shcath.
Fig. 5. .1/ gigantruin, 11. .1tp. Ideal transverse section of the vcntrel nerve-cord, passing through the roots of two of the large nerves, and through one
thin transverse commissure where a pair of large ganglionic cells is situated. The litera-significations are the same as in fig. .»• Some cells, e. g. c.’, which are connected with the
thick transverse commissures, arc also illustrated in this figure, C. I’air of large cells corresponding to c.’ in fig. 3 the prolongations or these cells arc seen to be in communication
with the fibrillar mass of the longitudinal commissure by means of suull lateral branchlets, as shown in fig 6 f. c.° Multipolar cell; situated at the root of a nerve and, sending a
prolongation, directly, into the nerve r.*. Cisjji witn spreading reticulated prolongations, situated among the cells indicated at tv’ in lig. 4. ;’.". Cells «hose prolongations become
loosened out among the longitudinal nervous tubes. 4 Kopte of nervous tubes originating in the fibrillar reticulation on the exterior dorsal side of the longitudinal commissure ; most
of the tubes, emanating from tlu- reticulation, arc seen to originate in the ventral part of the fibrillar mass of the longitudinal commissure (1).
Fig. 6. M gigautcavi, n. sp /.ciss I Oc. 1 Cam.-luc. Borax-carmine, Picric acid). Different forms of ganglionic cells, with spreading reticulated
prolongations, illustrated from transverse sections, b. and c’. Unipolar and multipolar cells, situated iu the fibrillar mass of a longitudinal commissure (I. Cell with prolongation
which, for a considerable distance, remains individed.
Fig. 6 e. Zeiss l’". Oc. 1. Cam.-luc, Large ganglionic cell with reticulated prolongation, corresponding to r,1 in fig. 4, and to Pl. V, lig. 9 d. and fig. 12 ne.-
Fig. 6 f. \rbitrary magnification.) < ianglionie cell wlio.se prolongation, directly, forms a nervous tube. In rajs figure, branchlets (gr.) issuing from the prolongation
tire indicated. I think that these bring the prolongation into communication with the fibrillar rcticulatiori, and that the nervous tubes arc, thus, brought into communication with each other
Fig. 6 g. I/, ff r n f fit " N/’■ (Zeis-» hom. im, ’/ih- ’t "’c. 1 Ganglionic cell from the ventral side of a longitudinal commmissure. The cell lias one prolongation,
Which forms, directly, a uervous tube, but there is. however, another prolongation (if), which appears a* if it issued from the nucleus. I question this, however, and in spite of the
must minute examination with a Zeiss ’/,„, could arrive at no certain determination.
Fig. 7. M. ffl’dffi, a. (Zeiss 1*. Oc. 1 Cam.-luc.) Longitudinal section of a large nerve, close to its root (.portion of a transverse section of the budyi,
showing ganglionic cells [nc., 7ic.’) situated within the fibrillar mass of the nerve. It appears as if the two cells were united at zs.; there is a protoplasmic thickening at this spot.
k., k.’ . hConne .tiv.-lissue nuclei situated in, or at, the sides of the fibrillar mass. Jc.\ Connective-tissue nuclei, situated in the reticular connective-tissue [ft.) surrounding the
nerve, and having communication with the neurilemum-sheath |;/.a7i ).
Fig. 8. (Zeiss nom. im. ’/,„. Oc. 1 ) Section of ganglionic cells, with nuclei in different stages of division (direct division. .. «., a’., b. Cells of ille
ncntrnl nerve-cord of M. graffi, a. sp. r. Cell of llu- fibrillar mass of the oesophageal-ring of M. giyanleum, n. sp. In this cell, distinct indications of a cellular segmentation
similar to that of a leucocyt, are seen.
Fig. 9. M. yraffi, n. Hp. Zeiss hom. im. ’/i* Cam.-luc.) Ganglionic cells of the ventral ncrve-cord which have 1 think, just undergone division; the
prolongations arc, as yet, still united.
Fig. 10. M. graffi, n. up Zeiss K Oc. 2. Cam.-luc. Korax-carmine, Picric a did.) Transverse section of a nerve root of the 6th pair of fine nerves, \ide
Pl. V., fig. 3, showing the cylindrical structure of the nervous tubes; the latter vary, considerably, in thickness. Connective-tissue nuclei are seen, situated in the inner
neurilemma-shcath. The outer neurilcinma-sheath is very thick.
Fig. II. M. gig antrum, 11. sp. (Zeiss l’ Oc. 2. Cam.-luc. Section of a nerve, which, in the bulk of the figure, passes along the nervous tubes but at tlu
end of the figure transsccts them obliquely, owing to a curving of the nerve, the cylindrical structure of the nerve, thus, becomes apparent, and the dark coloured fibrils are seen to
be. the septa of spongionlasm which enclosing the nervous lubes.
Fig. 12. (Arbitrary magnification? Two portions of nervous tubes traversing one of the longitudinal commissures, and issuing from ganglionic cells; showing
the slight tumefaction of the tubes at the point where branchlets arc given off to the fibrillar reticulation.
Fig. 13. M. giga)itntm, 11. SJ). (Arbitrary magnification ) Portion of horizontal section of a longitudinal commissure at the point where a large nerve is given
ofT, illustrating, schematically, the different types of nervous tubes received by a nerve from the ventral cord. 1. Nervous tubes passing through the large transverse commissures
arni emanating from ganglionic cells, or the fibrillar reticulation of the opposite side. 2. Tubes originating in the bundle of longitudinal uervous lubes (It. running along the inner
side of the longitudinal commissure. 3. Tubes originating m the fibrillar reticulation. 4. Tubes originating in the smaller bundle of longitudinal nervous tubes (/./" t running
along the outer side of the longitmlinal commissure c’ Ganglionic cells which send their prolongations, through the longitudinal commissure, into the nerve. < *. Ganglionic cells
corresponding to those indicated by in fig. 3. r\ Cell with spreading reticulated prolongation. n$k. Neurilcmma-sheath.
Fig. 14. M. gujantt ’inn, 11. ttp. (Zeiss I*. Oc. i. Cam.-luc.I Transverse section of an intermediate nerve, at a point where a branchlet is given off. The
bi.inchlet is seen to consist of small lul.es issuing, one from each of the few thick longitudinal nervous tubes of which the intermediate nerve is composed.
Fig. 15. M t/raffi, n. *■/> Zeiss hom. im «/,.. Oc 2 Cam -luc.) Connective-tissue nuclei.
Fig. 16. .1/ glabrum, /’ S. 1. Arbitrary magnification Secliou of the striate, ciliated cuticle covering the glandulotis tissue of a segmental glandulous sack
At uniform intervals, broader, non-striate spaces (a.) occur (probably secretive pores?). The roots, alone, of the cilia arc seen.
Fig. 17. M. <ira//i, 11 sp. Arbitrary magnification.1 Ideal, horizontal section, illustrating the alimentary canal, and ranification of the intestinal branches
tg f!l1 ■. tg’. The cloaeal canal is considerably shortened in the figure (vide fig. 201. a. Annular epithelial protuberance demarcating the oesophagus from the stomach.
11 r Annular constriction, dividing the stomach into anterior and posterior divisions. The constriction is, here, much drawn back and the division, consequently, is not ver\ distinct
h. O’. Septa separating the intestinal branches, c. Annular constriction separating the stomach from the cloacal canal. Old. Latero-ventral oviducts opening into the cloaeal cann!
an Cloacal aperture, tr. Tentacular ncrvc-ring. or. Oesophageal ring. n.c. Ganglionic cells situated, anuularly, around the oesophagus, at the posterior extremity of the proboscis
fl.c’. Ganglionic cells surrounding the tentacular nerve-ring
Fig. 18. .1/ rarpcnteri Ideal, horizontal section similar to that in flg 17. The litera-significations are the same as in fig. 17 The oesophagus (o».l is, here
pretty long and surrounded by muscles and ganglionic cells. The subdividing of the stomach is very distinct, its anterior part is subdivided by a small annular constriction (ill.
Fig. 19. .1/. gig as, Lik Ideal, horizontal section similar to those of the two preceding figures. The litera-significatiJns are the same as in figs 17 and iS
In this species, and, olso, in M giganteum, two pairs, only, of intestinal branches (tg.tg.") issue from the stomach. The subdivision of Ille stomach is distinct, rg Large groups
of ganglionic cells surrounding the oesophageal-ring or ). The cerebral ganglia are, in this species, largely developed.
Fig. 20. ,1/ graffi, 11. sp. (Zeiss AA. Oc. 1. Cam-luc Longitudinal section through the middle of the body, showing the situations of the alimentary canal,
the nervous system, and the oviducts. The course of 11 lateral oviduct is shown in Ille figure, iu order to illustrate its situation ’in relation to the nervous system and alimentary
canal, althrough it, "f course, is really, situated morr laterally. WW. Mouth, oc. Annular constriction separating the oesophagus from the stomach, a r. Annular constriction subdividing
till stomach il. Annular constriction, through which there is .ml; .1 very narrow passage into the cloacal canal, an. Cloacal aperture. Ovct Dorsal oviduct. 11 Origin of
later»-ventral oviduct. ot><f . out l’, l.atcro-vcntral oviduct, b. Opening of the oviduct into the cloacal aperture, ov. Ova. c. Portion of the body-cavity, in which ovn are situated.
b.s. \ entral ncrve-cord tnn. Thick transverse commissure at the anterior extremity, and In» ’ the similar commissure at the posterior extremity of the ventral nervc-cord. o.rm. Root
of oesophageal commissures 11. nth pair of tine nerves. Or. Oesophageal ring. tr. Tentacular ncrvc-ring. m.b. Muscular bulb.
Fig. 20 a. (Zeiss AA. Oc. 1. Cam.-luc.) Portion of a longitudinal section, of the same animal, as in fig. 20, but passing somewhat more laterally, mid illustrating
the .ourse of a latero-ventral oviduct. OVil. Portion of the dorsal oviduct (uterus’i. our/.’, opr/.-, Old Latero-ventral oviduct 1.1 which ova are situated, n r. corresponds to n r. in
Ug 20. I» 0. Muscular bulb. (1// .Intestinal branch. 11. Nerves, v.il. V&s deferens, p.’, p.’. Third and fourth parapodia. A. Chief hook. s.h. Supporting rod. m. Müjblej
converging in the parapodia.
. ., . Fl6; 2|. giganteum, 11. sp. (Zeiss AA. Oc. 4. Cam.-luc.; Transverse section of the alimentary canal, at the demarcation of the stomach and the cloacal
Sana . m.r LMtam or the epithelium ..f the stomach. r;i. Annular muscles surrounding the stomach, km. Kadial muscles w’. Small muscles situated in the walls of the cloacal
canal, on« Opening ..I the latero-ventral oviducts into tlu- cloacal canal. OVd. Dorsal oviducts, or Ova in the cloacal canal. 1 High epithelium on the ventral side ..f the
cloacal canal, it is seen to be much lluttencd on tne dorsal side of the anterior part. ,>. Ventral ectoderm.
i 1 F’o 22 , " ygaiitniiii, n. sp, (Zeis, F. Oc. 1 Cam.-luc.I Transverse section of epithelium (me.), and the wall of the stomach, iu which are situated annular
muscles m ■ and small radial muscles -nil.). «. Cells which send a prolongation towards the annular muscles or the epithelium (possibly nerve cells’).
, „ .... E , , ■"’’!!"!’"■, ’""fl- (Arbitrarj magnification.) Ideal, horizontal section, showing the situation of the oviducts and the form of the uterus and the
rf’f ss’eoii,I Wr I 0V°’ ." ’.hc ",crus’ and’ alo°6 ,h« WÄlls of «hese branches, minute ova are seen to be situated covering the walls as an epithelium,
t Xl hU Z . " Of the ovarium or body-cavity ,,, tlu- dissepiments trans,ected bundles or muscles are seen. d". Indications ofs^nall dissepiments, a. Con-
m situated over the anterior part of the al.ment.rj canal and the proboscis, ord. Dorsal oviduct, ovd:. Origin of latero-ventral oviducts.
observed Similar ova Wheih«^’ihis^ „ü",’!!.’ ’’ i /c-T K °C ’’ Scction of ova in Process or segmentation, situated in Ihe cloacal canal. I have, frequently,
obsened similar ova. Whether tins segmentation begins without a prior fertilisation, as Graff supposes, I am unable to sav. I am, however, more inclined to think that they are
fertilised by occasional spermatozoa passing through the cloacal aperture, into the cloaca! canal, along with the water ’ 7
<< prev. page << föreg. sida << >> nästa sida >> next page >>
