I 



ROTELLA. I 



Found in tlie seas of tropical climates, a circumstance 

 in wMcii it differs from the Helicinco, wliicli are land 

 shells, whose lip is reflected and whose callosity does not 

 expand far heyond the umbilicus; its operculum, more- 

 over, is obtusely triangular and not spiral; Lamarck, 

 therefore, judiciously excluded the^Rotella from the He- 

 licina, with which he had formerly united it. 



A little fossil shell occurs, in a stratum similar to the 

 Calcaire grossiere of the Paris basin, at Hauteville, near 

 Valognes, which we do not hesitate to refer to this Genus, 

 although it has a minute iimbilicus pierced -as it were 

 through the umbilical callosity, and its aperture is 

 rounder : it is the Turbo Helicinoides of Defrance. Several 

 Lias fossil shells, published in Mineral Conchology,'' 

 tab. 10. 273 and 285, are more nearly related to this 

 Genus than to Helicinay but they all have evidence of a 

 sinus in the center of the outer lip, in which respect they 

 neither agree with Helicina nor Rotella; though we pos- 

 sess a Rotella with a very slight indication of it. 



Fig. 1. Rotella monilifera. ^ 



2, — vestiaria. 



3, ■ aiicta. 



