Figs. 6 and 7 are from one drawing.
Fig. 6.Peripatus capensisdissected so as to shew the alimentary canal, slime glands, and salivary glands; × 3. (From a drawing by Miss Balfour.)
Fig. 7. The anterior end of Fig. 6 enlarged; × 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 anS-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, × 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 ofPeripatus 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 ofPeripatus 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.andi.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 (M1), 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 (M1).
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.M1. 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 ofPeripatus 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.M1. 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 ofPeripatus 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.RegionNo.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 ofPeripatus 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 ofPeripatus capensisenlarged 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 ofPeripatus 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 ofPeripatus 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. (ZeissC, 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. (ZeissA, Hartnack's camera.)
Plate 52.
Fig. 26. Portion of ventral cord ofPeripatus capensisenlarged, 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 ofPeripatus 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 ofPeripatus 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. RegionNo.2 of coiled tube of nephridium, lined by small closely-packed columnar cells.s.c.3. RegionNo.3 of coiled tube of segmental organ, lined by large flat cells with large disc-shaped nuclei.s.c.4. RegionNo.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 ofPeripatus 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. (ZeissB, 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. (ZeissE,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 ofPeripatus 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 ofPeripatus 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. (ZeissE,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 ofPeripatus 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 ofPeripatus capensis; ventral view. All, excepting Fig. 37, from drawings by Miss Balfour. In figures 34 to 38adenotes 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 ofPeripatus capensis. I could not tell for certain which was the anterior end. Length, 1.34mm.”
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 ofPeripatus 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.
[6]The explanations of the figures printed within inverted commas are by Professor Balfour, the rest are by the Editors.
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TRANSCRIBER'S NOTE: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 plate explanation.Changes for consistency within the text of the book:body cavity to body-cavitybody wall to body-wallchoroid-slit to choroid slitdevelope(s) to develop(s)Elasmobranchs to Elasmobranchiiinter-renal to interrenalre-agent(s) to reagent(s)omphalo-meseraic to omphalomeseraicpleuroperitoneal to pleuro-peritonealproto-vertebra(æ) to protovertebra(æ)re-appear to reappearside-fold to side foldsub-intestinal to subintestinalsub-notochordal to subnotochordalurino-genital to urinogenitalSpelling change:[TN 1]changed from 'Tranverse'
TRANSCRIBER'S NOTE:
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 plate explanation.
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)
Elasmobranchs to Elasmobranchii
inter-renal to interrenal
re-agent(s) to reagent(s)
omphalo-meseraic to omphalomeseraic
pleuroperitoneal to pleuro-peritoneal
proto-vertebra(æ) to protovertebra(æ)
re-appear to reappear
side-fold to side fold
sub-intestinal to subintestinal
sub-notochordal to subnotochordal
urino-genital to urinogenital
Spelling change:
[TN 1]changed from 'Tranverse'