Tompsett, D.H. 1939. Sepia. Liverpool Marine
Biological Committee Memoirs. 32: 184 pp. London. Williams and Norgate.
Plate 12, Figures 37-46.
Fig. 37. Dorsal dissection of
the buccal mass. The buccal mass has been exposed by opening the peri-buccal
sinus (P.B.S.) along the mid-dorsal line. The dorsal half of the jaw muscles
and of the retractor muscles of the buccal mass have been cut away. The dorsal
jaw has been removed, and it is shown in Figure 38 displaced to one side, but
otherwise as it would appear in situ, covering the palatine lobes (P.L.). The
left wing of the ventral jaw (V.J.) has been cut away. The right palatine lobe
has been pulled to one side to show the opening (O.A.S.) of the anterior
salivary gland. The anterior part of the horny lining (H.OES.) of the
oesophagus, which extends forwards between the palatine lobes to their
anterior extremity has been removed. The peri-oesophageal sinus is represented
as being cut through posteriorly, to show the buccal arteries (B.A.),
oesophagus (OES.), and duct (D.S.G.) of the posterior salivary glands, which
lie in it. The whole buccal mass has been pulled forward, so that the figure
might be clearer. In consequence the blood sinuses appear to be larger than is
actually the case in an undissected specimen.
Fig. 38. Dorsal view of the
dorsal j aw. The horny lining of the oesophagus (H.OES.) which is attached to
the posterior end of the jaw has been left adhering. The dorsal part of this
jaw forms the dorsal wall of the groove between the palatine lobes which leads
to the oesophagus.
Fig. 39. The anterior part of
the radula: posterolateral view. This is a diagrammatic figure to show the way
in which the radula membrane (Fig. 40, R.M.), bearing the horny radula, fits
over the odontophore (OD.), which is U-shaped in cross section. For the
explanation of the cut surface see Figure 40, which shows this surface in full
view.
Fig. 40. Transverse section
through the anterior part of the radula. This figure, which was drawn from a
hand section, shows the odontophore (OD.) supported by paired cartilaginous
rods (R.C.). The teeth shown are young ones which are not sufficiently
anterior to be yet in use. Muscles (R.R. and A.R.) which pull the radula to
and fro over the odontophore are shown. They lie in the radula membrane (R.M.).
Fig. 41. Transverse section
through the radula, rather more posterior than Figure 40: drawn from a hand
section. This figure shows the radula gland (R.G.) which secretes the radula
teeth, and the horny cuticle from which the teeth project. Part of the left
palatine lobe (P.L.) is shown. This contains the anterior salivary gland (A.S.G.).
The right palatine lobe has been cut away at the base. Cut ends (M.J.) show
where the radula-tongue assemblage was attached to the jaw muscles which form
the outer part of the buccal mass.
Fig. 42. Three rows of radula
teeth. (After Naef.).
Fig. 43. Longitudinal section
through the inksac, and the anterior part of the rectum, to show the general
structure. In the ink gland two zones can be recognised, a clear central one (C.I.G.),
and an outer zone (P.I.G.) in which the cells are forming pigment.
Fig. 44. The jaws: lateral
view. The dorsal jaw has been displaced dorsally from the position it occupies
relative to the ventral jaw, as otherwise the latter would partially obscure
it.
Fig. 45. Part of a single
lamina from the wall of the spiral caecum, to show the ribbed structure, which
increases its surface.
Fig.
46. Stomach and caecum opened, to show the gross structure. The figure is
somewhat diagrammatic. Most of the ventral wall of the stomach (ST.), the
vestibule (V.) and the caecum (CA.) have been removed, but the ventral part of
the groove (G.C.S.) along which thc secretion of the digestive glands is
conducted to the stomach, has only been cut through, and the walls pulled
apart. The stomach is completely lined with horny material (H.S.). This
lining, however, is very thin except in the region of the circular grinding
muscle (C.M.S.). Three sphincter muscles (S.S., S.C. and S.I.) are shown in
the vestibule, a region with which the stomach, caecum and intestine all
communicate. These muscles control the direction of flow of the contents. The
surface of the caecum is greatly increased by numerous laminae (L.CA. and Fig.
45) which lie radially, though only some of them stretch right from the
columella to the periphery.
Key to Abbreviations
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