MOLLUSCA. 169 
which communicates with it, and again contracts and unites 
with its fellow from the opposite side, to form the auricle. 
A single aorta arises from the anterior side. The ovarium 
is conical, and divided into numerous lobes. Behind, two 
ducts seem to arise, and to proceed one to each side; but 
it has not been determined whether they open externally. 
No male organs have been detected ; nor is there any thing 
accurately known with regard to the peculiar nature of their 
hermaphroditism. 
Genus Puyiimr1a.—aAnus placed dorsally near the ex- 
tremity of the cloak. The body, in the animals of this 
genus, is ovate. The foot is narrow in front. The cloak 
is broad, coriaceous, and destitute of a shell. Towards its 
anterior extremity are two cavities, from which issue the 
retractile superior tentacula, as in the genus Doris. Nearly 
at the posterior extremity is another cavity, containing the 
anus. This opening, though similar in situation to that of 
the Doris, is merely a short simple tube. The head is im- 
mediately above the anterior margin of the foot, above which 
is the mouth, having a small conical feeler on each side. 
Under the margin of the cloak on the right side, and about 
half way between the mouth and the middle of the body, 
are two openings, in a tubercle, for the organs of genera- 
tion. The branchiz consist of slender complicated leaves, 
which surround the body between the foot and the cloak. 
The circle is interrupted at the head and at the tubercle cf 
generation. The mouth is destitute of jaws. The gullet is 
simple, ending ina membranaceous stomach. The pylorus 
is placed near the cardia, and the intestine goes directly to 
the anus. The salivary glands are small, and placed near 
the mouth. ‘The liver is large in proportion. The heart is 
situate in the middle of the back. The auricle is simple, 
I 
