210 



POPULAR CONCHOLOGY. 



float) is two-lobed, which makes the transition to the dis- 

 tinct foot-fornied appendage of Cuvier ; the mouth has a for- 

 midable apparatus for seizing prey, and the tongue is armed 

 with recurved hooks. — 5 species. 



The Indian and Atlantic Oceans produce these curiously 

 delicate little shells ; many of them have the appearance of 

 the finest and thinnest glass. D'Orbigny says they appear 

 in myriads on the surface of the sea, about twilight on 

 calm nights, and that they disappear about day-break. 

 " An interesting fact noticed by Mr. F. Debell Bennett, 

 is that the C. cuspidata, which is found floating in great 

 numbers on the surface of the sea in various parts of the 

 Pacific Ocean, exhibits a speck of delicate blue light 

 shining through the apex of its extremely thin shell."* 



Balantium. Leach. — Shell triangular, depressed, 

 transversely waved, aperture oblong, narrow and oblique. 

 Animal not essentially different from Clio. — 4 species. 



From the seas of Guinea. 



Vaginella. Daudin. (Vaginula Sow.). — Shell oblong, 

 ventricose, smooth; apex conical; aperure contracted, trans- 

 verse, without any lateral slit. — Fossil, 1 species (Gray). 



Creseis. Bang. — Shell thin, fragile, transparent, py- 

 ramidal, pointed, a dorsal ridge produced into a point 

 at the edge of the aperture, f — 6 species, also 

 fossil. 



C. Spinifera, so called from its resemblance to a 

 thorn, is found in the Mediterranean. 



Theca. Sharpe. — Shell " sheath-shaped, with spmf&4 

 a triangular opening, flat, or slightly rounded posteriorly, 

 rounded or angular in front, marked with numerous lines 

 of growth." — 2 species, fossil. 



* Pro. Zool. Society, 1837. 



t Sow., Conch. Manual. 



