215 
excepting Dillwyn under tlie P. opercularisj L. Mr. Conrad con- 
siders the dislocatis as identical with the purpuratus, Lam. Plate 
66, fig. 2, 2a. 
Nassa. — Shell univalve, suhovate, ventricose, or subturreted, 
acute ] aperture suhorbicular, emarginated and reflected at base ; 
labium with a more or less dilated callosity or calcareous deposite ; 
labrum striated or sulcated within ; operculum horny ; animal de- 
pressed : tentacula two, conic-cylindric, inflated at the eyes ; eyes 
near the exterior middle 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 branchial 
cavity j branchiae pectiniform, unequal, nearly parallel ; male organ 
on the right side of the neck ; anus on the right ; foot large, 
prominent and angular before, attenuated behind. 
Ohs. Deshayes informs us that Klein first used this generic 
term for some shells of a reticulated surface, having a fancied 
resemblance to the ^^Nasse d^osier’^ or willow net of fishermen. 
Ijamarck, however, first separated the present genus from the Lin- 
iiaean Buccinum, but has subsequently reunited it as a subgenus. 
In this arrangement many distinguished authors coincide, as 
Cuvier, Blainville, Ferussac (in his Tabl. Syst.) and Deshayes. 
Sowerby and some other naturalists still separate it as a distinct 
genus nearly related to Cassis : Montfort carries the division still 
further, and divides the Nassse, into Phos, Alectrion and Cyclops, 
and Schumacher has also separated from it a few, species, under 
the name of Nana, neither of which have been admitted by 
the best authorities ) and it is not improbable that Nassa itself 
may be ultimately admitted universally as only a subgenus of Buc- 
cinum. 
The species are numerous and are both recent and fossil. They 
feed on animal food and they sometimes devour the animal of 
some bivalve shells such as Tellina alternata, S., and one of the 
valves of this species often exhibits a neatly formed, round per- 
foration, near the umbo, bored by a Nassa. These shells !_are 
sometimes smooth, but more generally with impressed striae or 
grooves ; others are reticulated so as to appear granulated or tuber- 
culated. 
A remarkable, depressed and even transverse species, the neritea, 
L., of which Montfort formed his genus Cyclops, differs so much 
