378 UNITED STATES GEOLOGICAL SURVEY OF THE TERRITORIES. 



in which the inner lip, or pillar, as he terms it, is described as having "at the 

 base two or three obtuse and very transverse plaits." I am therefore inclined 

 to think that Dr. Stoliczka was not familiar with Swainson's diagnosis, and 

 defined the group more with the view of making it conform to the charac- 

 ters • of the Cretaceous species before him, than he would have done from 

 Swainson's recent typical species and its nearer allies. At any rate, his Cre- 

 taceous species, so far as can be learned from his figures and descriptions, 

 have the columella, or inner lip, smooth anteriorly, and without a tooth, or even 

 other ridges or furrows posteriorly, than such as are produced by the surface 

 revolving ridges passing around the body-volution into the aperture. Con- 

 sequently, in making Tritonidea include these shells, it is necessary to define 

 it so as to make it exclude entirely shells conforming to Swainson's diagnosis. 

 Hence, it seems to me that if these Cretaceous species, including one herein- 

 after described, are to be referred to this genus at all, we must establish a 

 third section for them, and not place them in Tritonidea, either as a subgenus 

 or otherwise. Adopting this view, the three divisions may be defined as 

 follows : 



1. cantharus, Bolten (typical). 



Shell with canal very short, inner lip thin, and generally trans- 

 versely grooved along its entire lejigth, often toothed behind. — (Exam- 

 ple as already stated.) 



2. tritonidea, Swainsou. 



Shell with canal more produced; inner lip with usually two or 

 three obtuse, transverse plaits anteriorly, and sometimes a posterior 

 tooth or projection. — (Buccinum undosum, Linnaeus.) 



3. cantharulus, Meek. 



Shell with canal moderately produced, rather narrow and twisted ; 



inner lip smooth throughout, and rather well developed; columella 



arcuate and twisted, so as to form an obtuse, undefined prominence 



below ; outer lip slightly sinuous above.— (Futms Vaughani, Meek and 



Hayden.) 



The type of the last of the above-defined sections is a moderately thick 



shell, and has its inner lip well developed below, and rather thinly spread 



upon the body-volution above, so as to extend a little beyond the edge of the 



outer lip, which is only very obscurely furrowed just at the inner edge, a 



