NASSA. 



GENERIC CHARACTER. 



Shell univalve, subovate, ventricose, or sublurreted, 

 acute ; aperture suborbicular, eniargiiiated and reflected at 

 base ; labium with a more or le^s dilated callosily or calca- 

 reous deposite ; labrum striated or sulcated within ; oper- 

 culum horny ; animal depressed ; tentacula two, conic- 

 cjlindric, inflated at the ejes ; eyes near tlie exterior mid- 

 dle of the tentacula ; proboscis very short or obsolete ; 

 mantle folded into a distinct tube before ; orifice of the 

 oviduct situated on the right at the opening of the bran- 

 chial cavity ; branchiee pectiniform, unequal, nearly paral- 

 lel ; male organ on the right side of the neck ; anus on 

 the right ; foot large, prominent and angular before, at- 

 tenuated behind. 



OBSERVATIONS. 



Deshayes informs us that Klein first used this generic 

 term for some shells of a reticulated surface, havinii; a fan- 

 cied resemblance to the '• Nasse d'osier" or willow net of 

 fishermen. Lamark, however, first separated the present 

 genus from the Linmean Buccinum, but has subsequently 

 reunited it as a subgenus. In lliis arrangement many dis- 

 tinguished authors coincide, as Cuvier, liiainville, Ferus- 

 sac (in his Tabl. Syst.) and Deshayes. Sowerby and s^me 

 other naturalists still sep.Tratc it as a distinct genus nearly 



