12 
Prof. R. Owen on the Anatomy 
upon themselves at acute angles, and of minute granules. A 
slight pressure destroys the form of most of these filamentary 
groups *. 
The right branchial vein (?) crosses, dorsad of the branchial 
heart (reflected upward in fig. 3), in the form of a cylindrical 
canal, and enters the smaller end of a transversely extended 
systemic ventricle (a) ; the left branchial vein (?) enters the 
opposite end. Each branchial vein is continued from the 
ventral side of the gill-base. 
The systemic heart-substance, or u bulbus arteriosus” [k), 
bends forward at right angles to the main ventricle (a), and 
near the entry of the right branchial vein («'). A smaller 
posterior aorta (/) is given off from near the middle of the 
back part of the transverse ventricle. This aorta supplies the 
nidamental glands and succenturiates, the hemispheric mass of 
the last shell-chamber, also the capsule applied to the umbilical 
parts of the shell-whorls. 
From the inner surface of the ventral part of the mantle, 
distad of the border of the pallial valve, a vein emerges; on 
the inner surface of the dorsal part of the mantle are glisten¬ 
ing bands of transverse fibres intercepting orifices or trans¬ 
verse slits of the sinus continued from the veins from the 
“ retractores capitis ” and salivary glands. 
The gills (PI. II. fig. 1, a, a!-, PI. III. fig. 3 ,g,g') are two 
in number, of the same structure as in other Dibranchiates; 
they are rather larger, relatively, than in Loligopsis , but have 
the same number of laminae (twenty-four pairs). From the 
basal half or rather more of the fleshy stem is continued the 
freenal fold above mentioned (PL III. fig. 1 ,f), the layers of 
which are continuous with the general serous membrane of 
the visceral chamber. The gill (a 1 in fig. 1, PI. II.) is 
reflected to show the opposite surface. 
The specimen confided to me for dissection was a female. 
The generative organs consist, as in Sepia, Septiola, and Rossia , 
of an ovary (PI. III. fig. 1, h), an oviduct (PI. II. fig. 3, e), 
with an oviducal gland (ib. fig. 3, d ; PI. III. fig. 6, d ), and a 
pair of nidamental glands (PI. III. fig. 1, c, c ; PI. II. fig. 3, c). 
The ovarium, filled with ovisacs, the largest of which are 
II millim. in diameter, occupies the left side of the fundus of 
the visceral chamber. The oviduct^ is continued from its an¬ 
terior part, and is soon dilated by ova, of large relative size, 
as in Sepiola and Rossia. 
* In the sac lodging the homologous follicles of the Pearly Nautilus, 
Van der Hoeven found “a calcareous reddish-white and friable con¬ 
crement : I believed it to contain uric acid ; but the chemical inquiry of 
Prof. Van der Booncliesch has not confirmed my supposition ” (“ Contri¬ 
butions to the Knowledge of the Animal of Nautilus pompilius," Transac¬ 
tions of the Zoological Society, vol. iv. p. 24). 
