TRUNCARIA. 1 1 1 



Sub-gen. ampiiissa, H. and A. Adams. 



Shell with the aperture anteriorly dilated, the contraction 

 near the spire obsolete. 



corrugata, Reeve. intincta, Reeve. 



Genus NORTHIA, Gray. 



Shell elongated, turreted, polished ; spire elevated, acu- 

 minated, whorls depressed and sloping at their upper part ; 

 aperture shorter than the spire ; outer lip with the margin 

 serrated. 



Ex. N. serrata, Dufresne, PI. 12, fig. 1. Operculum, 

 N. serrata, fig. 1, a, 1, b. 



This genus is of limited extent ; one species has been 

 described by Mr. Reeve, under the name of Pleurotoma 

 rissoides, and another in the " Zoology of the Voyage of 

 H.M.S. Samarang," under that of Buccinum alhopuncta- 

 tum. The large and typical species, Nassa serrata of M. 

 Dufresne, was formerly much prized by collectors, and in- 

 habits the shores of California. 



Species of Northia. 



albopunctata, Adams and rissoides, Reeve. 

 Reeve. serrata, Dufresne. 



Genus TRUNCARIA, Adams and Reeve. 



Shell acuminately oblong, thick; suture of the spire 

 channelled ; aperture anteriorly dilated, posteriorly sub- 



