MOLLUSCA. 445 



The head is divided into two lobes, the summits of which 

 are furnished with tentacula. The existence of eyes has 

 not been ascertained. The mouth is transverse, with two 

 lateral longitudinal lips. On each side of the neck arise two 

 blunt, conical, fin-like expansions, with a fine reticulated 

 surface, considered as serving the double purpose of fins 

 and branchia?. The anus and orifice of generation termi- 

 nate under the base of the right branchia. The viscera 

 do not fill entirely the cavity of the inner bag. The gut 

 makes only one fold. 



The genus Clio, was originally instituted by BROWN in 

 his Natural History of Jamaica. It was afterwards em- 

 braced and modified by LINNJEUS and PALLAS, in such a 

 manner, as ultimately to exclude the species for the re- 

 ception of which BROWN originally formed it. It con- 

 tains two species, the most remarkable of which is the Clio 

 borealis. Mr SCORESBY, in his valuable work on the 

 Arctic Regions, states (vol. i. p. 544.) that it occurs in 

 vast numbers in some situations near Spitzbergen, but is 

 not found generally throughout the artic seas. In swim- 

 ming, it brings the tips of the fins almost into contact, first 

 on one side and then on the other. 



10. CLEODORA Body covered with a triangular pyra- 

 midal tunic. 



The fins are membranaceous. The mouth is situate 

 between these, and is furnished with a semicircular lip. 

 This genus was instituted by PER ON, for the reception of 

 the Clio of BIIOWN. The C.pyramidata is the best ascertain- 

 ed species. BROWN'S Jamaica, p. 386, Tab. 43. f. 1. Two 

 other species were taken by the Congo Expedition, in S. 

 Lat. 2 14', and E. Long. 9 55', and S. Lat. 2 41' E. 

 Long. 9 16', u both having a spinous process on each side 

 of their shell, near its opening. One species is beautifully 



