26 DR. R. E. GRANT ON THE GENUS LOLIGOPSIS, 
markably wide, running along the free margin of each gill to the systemic ventricle. 
There are twenty two lamine in each branchia, which are, as usual, largest in the middle 
of the gill, and become gradually smaller towards both ends. The systemic ventricle is 
very muscular, though not larger than one of the branchial auricles ; it has a length- 
ened fusiform shape, with an aortal trunk from each end. The branchial veins enter 
it on each side near its upper and broader extremity, where the anterior or ventral 
aorta arises; the dorsal aorta passes up to the head behind the lobes of the liver. 
On the large dorsal or posterior aorta there is a distinct bulbous enlargement, as in 
Nautilus. This is probably the commencement of the bulbus arteriosus, which in higher 
classes of animals allows the aorta to be divided during the development of the vas- 
cular system, into the great pulmonic and systemic trunks. The great systemic ven- 
tricle is extended nearly in a longitudinal direction, and not, as usual, transversely. 
The two branchial veins! form slight bulbous enlargements before they enter near its 
upper and more dilated part ; and the anterior or smaller aorta, going to be distributed 
chiefly on the anterior parietes of the mantle, has also a slight enlargement at its origin 
from this rounded extremity of the ventricle. The large dorsal aorta, coming from 
the inferior narrow apex of the ventricle, passes first downwards and backwards to 
gain the dorsal surface of the mantle, then runs upwards, behind the liver and eso- 
phagus, along the middle of the back, between two large nervous cords, to the head, 
giving off numerous branches in every part of its course. These two large parallel 
nervous cords® descending along the middle of the back, like the two columns of the 
spinal marrow of Vertebrata, arise from the two great ganglia placed close together at 
the upper and back part of the mantle, and can be traced downwards, preserving their 
parallelism, and giving off numerous nerves in their course, to the base of the mantle 
below the organs of generation. They take their course along the middle of the dorsal 
lamina. 
The specimen was a female, and the developed condition of the ovaria and ova showed 
that, though a small animal, it had arrived at maturity. The ovarial sac, closely at- 
tached to the base of the stomachs, though filled with completely developed ova, oc- 
cupied but a minute portion of the capacious cavity of the mantle; all the wscera 
together did not occupy nearly a quarter of this cavity. The ova‘, of a pyriform shape 
and nearly of the same size, hanging in dense clusters which distend their sac, are at- 
tached by their tapering end, and exhibit a darker-coloured opaque central yolk sur- 
rounded by a thinner and more transparent fluid. The capsule of each ovum does not 
present the white opaque reticulate markings so common in the larger Cephalopods ; 
and the usual large glands of the oviducts appear to be wanting. 
This little animal constitutes a new form in the class of Cephalopoda, a highly inter- 
esting group, connecting, by obvious characters, the simple structure of Gasteropods 
1 Fig. 8. 2 Figg. 5. 6. 3 Figg. 4. 5. * Figg. 9. 10. 
