GASTEROPODA 21 



MiTRA, Lam. 1801. 



Gen. Char. Shell turreted, elongated ; spire elevated, apex generally acute ; 

 volutions smooth, striated, sulcated, or, more frequently, costated ; columella slightly 

 recurved and plicated ; folds less oblique than in Voluta, the lower fold always the 

 smallest; aperture narrow and elongated; outer lip slightly thickened, and often 

 dentated. 



The greater part of the shells constituting this extensive genus, in the recent state, 

 are natives of tropical or subtropical regions, but its geographical range is very 

 extended, one species inhabiting the Greenland seas. Fossil species are by no means 

 abundant, although they are occasionally present in all the tertiary deposits. The range, 

 in depth, of many of the species is very considerable. Professor E. Forbes dredged 

 up Mitra ebena'm the Mediterranean, at depths varying from twenty to eighty fathoms, 

 and some are even littoral species. 



1. Mitra PLiciFERA. 8. JFood. 



Mitra plicifeka. S. ff^ood. Catalogue 1842. 



The shell that stands under this name in my Catalogue is a true Mitra, possessing 

 four folds upon the columella, the upper one the largest and most isolated, while the 

 lower one is small and nearly obsolete. It is obtusely costated upon the volutions, and 

 transversely • striated. My specimens are unfortunately in bad condition, unfit for 

 figuring, and all further notice respecting it must be deferred until some better pre- 

 served individuals are obtained. 



RiNGicuLA,* Deshai/cS:, 1838. 



AURICULINA. Grateloup. 1838. 

 Makginella. MSnard de la Groye. 

 Pepides. Dujardin. 

 Auricula (spec.) Lam. 



Gen. Char. Shell small and ovate, with a short spire and acute apex ; smooth or 

 striated externally ; columella callous, deeply plicated ; outer lip thickened and 

 reflected, with a deep notch at the base of the aperture. 



This is a marine genus, and on that account separated by Deshayes from Auricula, 

 in which these shells had been previously placed by Lamarck. It is in all probability 

 one of the zoophagous molluscs, as the deep notch for the syphon would seem to 

 indicate, though its place in a natural arrangement has not been well determined. 

 Few species are as yet known, and those sparingly distributed throughout the 

 tertiaries ; one is still living in the Mediterranean and one at the Gallapagos islands. 



* Etyin. The diraiuutive of riiigens (from riugo, ringere, to grin), the specific name of the tj^je of the 

 genus. The name of Aurimlina was proposed by Grateloup, iu 1838, for this genus, but the above name 

 had been previously (?) used by Deshayes, in the same year, iu the 2d edition of Lam. Hist, des An. sans 

 Vert., vol. viii. 



