158 Descriptions of New Species and Varieties of Shells, 



Stoasto^ta Philippianum. Shell siibdiscoidal, convex above : 

 pale horn color, subtransparent : surface smooth and shining: 

 spire moderately and convcxly elevated : whorls three and one- 

 half, slightly convex, with a moderately impressed suture ; 

 last whorl regularly rounded over the periphery, very slightly 

 detached from the penult whorl near the aperture : aperture 

 slightly campanulatc : labrum slightly produced beyond the 

 labium, not scalloped : labium in its upper half a little de- 

 tached from the penult whorl, with the lower half extending 

 below the penult whorl : umbilicus of moderate size, with the 

 spiral lamella excessively developed and usually soldered by 

 its exterior edge to the last whorl, forming over the umbilicus 

 a large arch, which has an opening rather larger than the 

 aperture of the shell. Inhabits Ackendown in AVestmoreland. 



Mean divergence about 130° ; height .055 inch ; least 

 breadth .09 inch ; greatest breadth .075 inch. 



Stoastoma Agassizianum. Shell subdiscoidal : horn color, 

 subtransparent : with, on the last whorl, four very prominent 

 sharp carinse, viz., one along the periphery, and two below 

 and one above, the latter appearing only for a short distance 

 on the penult whorl ; with a few fine raised spiral lines on the 

 upper part of the whorls and between the carina? : spire 

 slightly elevated : whorls three and one-half, planulate, with 

 a moderately impressed suture; last W'horl planulate beneath, 

 near the end rapidly descending and slightly detached from 

 the penult whorl : aperture very slightly campanulate : labrum 

 slightly reflected, rounded, not scalloped : labium : umbi- 

 licus of moderate size, with the spiral lamella excessively de- 

 veloped and soldered by its exterior edge to the last whorl, 

 forming over the umbilicus a large arch, which has an open- 

 ing much larger than the aperture of the shell. In the only 

 specimen now before me, there is, around the lip within, a 

 deposit which contracts the aperture, and rising over the labi- 



