MOLLUSCA OR UNIVALVES. 209 



The following genus, described both by Des- 

 hayes and Rang, will be introduced. 



75. ElSSOA (Freminville). — Shell oblong, 

 turreted ; no umbilicus ; generally remark- 

 able for its longitudinal bands ; mouth oval, 

 oblique; the two lips united, or nearly so; 

 the right not reflected, but thickened ; a 

 calcareous or horny operculum. Animal, foot 

 short and round. — 44 species, recent and fossil. 



The species of this small shell are brought 

 from the Mediterranean, the seas of Senegal, 

 and the European Ocean. They are generally 

 found on sandy shores. 



76. Delphinula. — Shell very thick ; spire 

 depressed; umbilicus large; 

 exterior rough, with tuber- 

 cles; mouth pearly; lips 

 united ; operculum shelly. 

 Animal, head distinct, having two tentacula, 

 with eyes at the base ; foot short and round. — 

 3 species recent, and 10 fossil. 



All the species forming this genus are found 

 in the Indian Ocean. Some of them have the 

 whorls entirely separated. 



p 



