TO GEOLOGY. 159 



to the opposite side it descends about the same distance ; 

 mouth subovate, rather contracted ; outer lip small, thin 

 and edged below, above thick and recurved. 



Length 2.2, Breadth .7, of an inch. 



Observations. This curious species of an interesting 

 genus, presents characters unknown in any with which I 

 am acquainted. Its most extraordinary character is that 

 of the deposit, coating the w T hole of the shell thickly over 

 except the lip ; this gives it a rude unshapen appearance. 

 It ascends and overtops the beautiful spire, and enclosing 

 it forms a new apex above. Young specimens present so 

 entirely a different aspect as to make it difficult to believe 

 they are the same species. They are gracefully formed, 

 and the superior part is covered with longitudinal, parallel, 

 flexed ribs fine transverse stria? cover the whole exterior 

 surface. In this state it closely resembles the young of R. 

 curvirostris (Lamarck). The figure represents a specimen 

 with the deposit removed from the apex, in which state 

 they often occur. Having six fossil species from Europe, 

 in my cabinet, I am able to make the following compari- 

 sons. It differs from the Strombus amplus (Brander), 

 (Rostellaria macroptera of Lamarck), in being without the 

 great wing which in my largest specimen expands 

 beyond and behind the top of the spire. It differs from the 

 R. longirostra (Grateloup) greatly in the deposit, this 

 species having little more than the columelia thickened 

 it differs from the R. columbata (Lamarck), which is thick- 

 ened only along the canal terminating near the apex it 

 differs from the R. fissurella (Lamarck), which is strongly 



