I 



STOMATIA. 



TESTA intern^ margaritacea, sub orbicularis, vel 

 oblonga, auriformis, depressa, spira plerumque 

 prominente, interdum inconspicua, marginali. 

 Apertura integra, plerumque longitudinalis, 

 vel suborbieularis, vel elongata, amplissima, 

 marginibus integris, supernfe conjunctis. 



In his observations upon Stomatella, Lamarck tells us, 

 that in respect to their general form, they appear to he 

 nearly related to the Stomatice ; and that they are prin- 

 cipally distinguished by the transverse ridge and the ele- 

 vated outer lip of the Stomatise. Upon a careful exa- 

 mination^ however, of ten species, we are unable to dis- 

 cover any difference in the outer lip ; and it will be ob- 

 served, that Lamarck places among his Stomatellae one 

 species, the S. rubra, which has a nodular keel placed 

 exactly in the same position as the transverse ridge by 

 which he characterizes Stomatia; so that, in fact^ we do not 

 find any generic difference whatever, and have therefore 

 united the two Lamarckian genera, under the appellation 

 of Stomatia, which has been long applied to one of them. 

 The Genus thus formed may be described as follows : 

 Shell pearly within, mostly coloured externally ; sub- 

 orbicular or oblong, generally ear-shaped and depressed. 

 In most species the spire is prominent, but not produced, 

 nor elongated ; sometimes, however, it is very small, 

 marginal, and inconspicuous. Aperture mostly longitu- 

 dinal, in some species nearly orbicular, in others much 

 elongated, always very large ; its edges entire, united at 

 the upper part, and scarcely modified or altered in form 



