PTEROPODA. 321 



ginated tail, and the division of the body, by grooves, into six 

 lobes, Encycl. Meth., PI. of the Mollusc, pi. Ixxv, f. 1, 2. 



Cymbulia, Peroii. 



A cartilaginous or gelatinous envelope resembling a galley, or ra- 

 ther a sabot or wooden shoe, bristling with small points disposed in 

 longitudinal rows. The animal has two large wings composed of a 

 vascular tissue, which are its branchiae and fins; between them, on 

 the open side, is a third and smaller lobe with three points. The 

 mouth with two small tentacula is situated between the wings to- 

 wards the closed side of the shell and above two small eyes, and the 

 genital aperture, whence issues a small penis in the shape of a little 

 proboscis. It is so diaphanous, that the heart, brain, and viscera 

 can be distinguished through the envelopes(l). 



Pneumodermon, Cuv. 



The Pneumoderma begin to be a little further removed from the 

 Elios. Their body is oval, without a mantle and without a shellj the 

 branchiae are attached to the surface and composed of little laminae 

 arranged in two or three lines so disposed as to form an H on the 

 part opposite to the head. The fins are small; the mouth furnished 

 with two small lips and two bundles of numerous tentacula, each 

 terminated by a sucker, has a little lobe or fleshy tantaculum be- 

 neath(2). 



Fneumodermon Peronii, Cuv. Ann. du Mus., IV, pi. 59; and 

 Peron, lb., XV, pi. 2. Not more than an inch long. This spe- 

 cies, which is the most common, was captured in the Ocean by 

 Peron. 



LiMACINA, Cuv. 



The Limacinae, according to the description of Fabricius, should be 

 closely related to the Pneumoderma; but their body terminates in 

 a spirally convoluted tail, and is lodged in a very thin shell formed 



(1) See Peron, Ann. Mus., XV, pi. iii, f. 10 — 11. N.B. In the fig. of Cymbulia, 

 given by Blainville, Malac., XLVI, the position of the animal in the shell is di- 

 rectly the reverse of the true one. Our description is founded upon the recent 

 and repeated observations of M. Laurillard. 



(2) M. de Blainville once thought that the fins supported the branchial tissue, 

 and that what I have considered as branchix is another kind of fin. In this case 

 the analogy with the Clios would have been greater; but since then, (Malacol., p. 

 483) that gentleman has adopted my views. 



Vol. II.— 2 Q 



