AND DISTRIBUTION OF THE FIROLIDA. 269 
of taste appear to receive their nerve-supply from the cephalic, and not from the buccal 
ganglion. 
The branchial nucleus is largely composed of a dark-red or brown rounded liver, which 
lies behind the stomach and rectum, bulging well into the former, and striated as if 
lobulated (Plate XLIIL fig.4, 1). Its minute anatomy requires further study ; but from 
its position near the posterior end of the intestinal canal, and not far from where the 
food makes its exit from the body, the secretion probably partakes more of the nature of 
an excretion than of one necessary to digestion. 
Absorption of the products of digestion is doubtless effected, as in the Mollusca gene- 
rally, by the venous lacune or sinuses which surround the œsophagus and fill up the 
periintestinal cavity, and doubtless totally distinct from the aquiferous ‘canals outside 
the muscular coat. Surrounded and bathed by the blood, the intestinal tube and sto- 
mach deliver the nutriment their lining membrane absorbs directly into that fluid, to be 
elaborated and applied to the purposes of assimilation. 
Generative System. 
The anatomy and physiology of the generative system, and especially the development 
of the ova and young, still require observation. Like the order generally, they are bi- 
sexual. A male organ is seen in many, consisting of a well-developed penis having a 
central canal, a terminal bulbous glans-like swelling, and two testicular-looking bodies 
posteriorly, each showing a central tube or excretory canal, which joins that of the penis. 
In Firoloides (Plate XLIII. fig. 1) this lies at or near the lower and anterior part of the 
branchial nucleus—but in Firola (Plate XLIII. fig. 4, ») some distance in front, and 
supplied with nerves both from the pedal and branchial ganglia, as in Plate XLIII. fig. 4, p. 
In Carinaroides pedunculata (Plate XLIV. fig. 16) and Carinaroides, Plate XLIV. fig. 14, 
it also occupied the right side, and is large and apparently sheathed and retractile. 
Its position probably varies, even in different species. A large ovary is said by some to 
form part of the visceral nucleus, lying behind and filling a concavity in the liver. A 
peculiar ‘appendage often projects from the terminal extremity of Firoloides, with a 
pediele sometimes short and thick (Plate XLIV. fig. 7), in others long (Plate XLIV. 
figs. 8, 9, 10), but with no swelling, perhaps from its having broken Of (Plate XL. 
fig. 1). Plate XLIV. figs. 5 & 6 are enlarged views of one variety with eight distinet 
segments, gradually increasing in size toward the free end, and each attached to its 
fellow above and below by an annulated constriction, as if they ultimately broke off 
and became detached. The largest compartment was empty, and could be flattened 
by pressure, appearing semiopaque under the microscope. The wall, thick towards 
its attached end, became gradually thinner towards its outer extremity, while the 
centre appears hollow and tube-like. No other peculiarity could be observed in their 
structure; and they were present in one form or another in nine out of twenty-threc 
Firole and Firoloides, and could be readily observed by the unaided vision. In spirit 
they shrivel slightly. 
