120 AMERICAN MARINE CONCHOLOGY. 



Family CAYOLINIDJE. 



Synopsis of Genera. 

 Body short, sometimes furnished with lateral appendages ; shell globular ; 

 mouth narrower than the internal cavity, with a lateral slit on each side, 

 interrupted in front. Cavolina, Gioeni. 



Body short, sometimes furnished with lateral appendages ; shell globular, 

 mouth narrower than the cavity, with a slit on each side, not interrupted 

 in front ; apex often truncated in the adult. Diacria, Gray. 



Animal elongate, conical, without lateral appendages ; shell elongate, an- 

 gular, conical ; mouth larger than the cavity, without any lateral slits. 



Clio, BroAvne. 

 Body elongate, conical, rounded ; shell elongate, conical, subcylindrical ; 

 mouth larger than the cavity, without any lateral slit. 



Sttliola, Lesueur. 



Genus CAVOLINA, Gioeni. 

 Desc. 1783. 



1. C. TRIDENTATA, Gmelln. Fig. 248. 

 Syst. Nat., 3348. 1790. 

 Shell yellowish, pellucid, thin, very finely striated transversely ; 



terminal tooth longer than the lateral ones. 



Martlia^s Vineyard. 



Dredged 20-25 fms. The distribution of this species is uni- 

 versal. 



Genus DIACRIA, Gray. 

 Syn. Brit. Mils. 1840. 



1. C. TRispiNOSA, Lesueur. Fig. 249. 



Blainv. Diet. Sc. Nat., xxii. 82. 1783. 

 Shell elongated, straight, dilated anteriorly, compressed on each 

 side, terminated posteriorly, with a very long spine, armed late- 

 rally Avith two short spines. 



Nantucket (Europe, Bio Janeiro). 



Genus CLIO, Browne. 

 Hist. Jamaica, 386. 1756. 

 Cleodora, Peron et Lesueur, Ann. Mns., xv. 1810. 



1. C. PYRAMiDATA, Linujeus. Fig. 250. 

 GmeUn, Syst. Nat., 3148. 1790. 



Shell triangular, pyramidal, short ; mouth obliquely truncated. 



