related to Cassis : Montfort carries the division still fur- 

 ther, and divides the Nassau into Phos, Alectrion and Cy- 

 clops, and Schumacher has also separated from it a fev^ 

 species, under the name of Nana, neither of which have 

 been admitted by the best authorities ; and it is not im- 

 probable that Nassa itself may be ultimately admitted uni- 

 versally as only a subgenus of Buccinum. 



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 pertoration, near the umbo, bored 

 by a Nassa. These shells are sometimes smooth, but more 

 generally with impressed striae or grooves ; others are re- 

 ticulated so as to appear granulated or tuberculated. 



A remarkable, depressed and even transverse species, the 

 neritea, L. of which Montfort formed his genus Cyclops, 

 differs so much in appearance from the usual form, that 

 Gmelin considered it a variety of vestiarius, L. the type 

 of the genus Rotella, and 1 observed it in a cabinet, arrang- 

 ed with species of that genus, from which it is in reality 

 so widelv distinct. 



NASSA UNICINCTA. 



DESCRIPTION. 



Shell yellowish-white, or cinereous, subovate-conic ; 

 whirls with numerous revolving lines and transverse un- 



ri. 57. 



