PTEROPODA. 205 



CLEODORA, Peron and Lesueur. 



Syn. Clio, L. (part) not Miiller. Balantium, Leach MS. 



Type, C. pyramidata, PL XIV. fig. 33. 



Shell pyramidal, 3 sided, striated transversely ; ventral side flat, dorsal 

 keeled; aperture simple, triangular, with the angles produced ; apex acute. 



Animal with rudimentary eyes ; tentacles obsolete ; mantle-margin with a 

 siphonal (?) process; fins ample, united ventrally by a' rounded lobe; lingual 

 teeth 1.1.1. The transverse bars of the gill, the heart, and other organs are 

 visible through the pellucid shell. In C. curvata and pellucida (Pleuropus, 

 Esch.) the mantle is furnished with two long filaments on each side. 



Distr. 12 sp. Atlantic, Medit. Indian Ocean, Pacific, C. Horn. 



Fossil. Miocene . Brit. (C. infundibulum, Crag.) 



Sub-genus. Creseis, Rang. (Styliola, Lesueur). C. aciculata, PI. XIV. 

 fig. 34. Slender, conical, pointed, straight or curved. Fins rather narrow, 

 truncate, with small tentacles projecting from their dorsal edges, and rudi- 

 ments of the mesopodium on their surface; mantle -margin with a spiral 

 process on the left side. M. Rang states that he has seen these pteropods 

 clustering round floating seaweed. Distr. 5 sp. (like Cleodora.) 

 CUVIERIA, Rang.* 



Dedicated to Baron Cuvier. Type, C. columnella, Rang, PI. XIV. fig. 35. 



Shell cylindrical, transparent ; aperture simple, transversely ovate ; apex 

 acute in the young, afterwards partitioned off, and usually deciduous. 



Animal with simple narrow fins, united ventrally by two small lobes ; 

 lingual teeth 1.1.1. 



Distr. 4 sp. Atlantic, India, Australia. 



Fossil 1 sp. (C. Astesana, Rang.) Pliocene, Turin. 



Sub-genus, Vaginella, Baud. V. depressa, PI. XIV. fig. 36. Shell oblong, 

 with a pointed apex; aperture contracted, transverse. Fossil, 1 sp. Miocene. 

 Bordeaux, Turin. 



THECA, Morris. 1845. 



Type, T. lanceolata. Syn. Creseis, Forbes.f Pugiunculus, Ban*. 



Shell straight, conical, tapering to a point, back flattened, aperture 

 trigonal. Lon. 1-8 inches. 



Fossil, 6 sp. Silurian. N. America, Brit., New South Wales. 

 PTEROTHECA, Salter. 



Type, P. transversa, Portlock, 3 sp. L. Silurian ; Ireland, Wales, Canada. 



Shell bi-lobed, transversely oval, with a dorsal keel projecting slightly at 

 each end ; ventral plate small triangular. 



* Under the name of " triptere," M.M. Quoy and Gaimard described the fragment 

 of a pteropod, since ascertained to have been a Cuvieria. 



f Creseis Sedgwicki, Forbes, is an orthoceras with very thin septa, belonging to the 

 same group with (Conularia) teres, Sby. Tentaculites, Schl. is anellidous. (Salter.) 



