149 



ed : umbilicus rather wide, with the spiral lamella moderately 

 developed. Operculum very deeply concave, auriculate at 

 both extremities, very finely punctulate. 



Mean divergence about 140° ; height .035 inch ; greatest 

 breadth .07 inch ; least breadth .055 inch. 



This species closely resembles S. Goidclia?imn, and is most 

 readily distinguished by the difference in size. A closer in- 

 spection will detect the more essential differences. 



Stoasto:\ia Tatpanianum. Shell subdiscoidal : pale horn 

 color, subtransparent : with seven spiral carinse, of which the 

 upper one is small and the lower one very minute, and of 

 which two are visible on the upper whorls ; with very deli- 

 cate spiral raised lines, usually one between the first pair of 

 carinas and two or three in each following interspace : spire 

 moderately and convexly elevated : whorls three and one-half, 

 moderately convex, with a deep suture ; last whorl scarcely 

 detached from the penult whorl near the aperture : aperture 

 rather more than a semicircle, a little contracted behind the 

 labrum, which is well produced, above rather abruptly pro- 

 duced, scarcely modified by the carinse ; labium much de- 

 tached from the penult whorl and a little reflected : umbilicus 

 rather wide, with the spiral lamella moderately developed. 

 Operculum very deeply concave externally, smooth, auriculate 

 at both extremities. 



Mean divergence about 140° ; height .045 inch ; greatest 

 breadth .086 inch ; least breadth .07 inch. 



This shell also resembles S. [Goiddiaman, and might be 

 mistaken for the young of that species. But the labrum is 

 thickened as in all mature shells of Stoastoma proper. It is 

 most readily distinguished from that species by the peculiari- 

 ties of the aperture. 



Stoastoma Hollakdianum. Shell subdiscoidal : pale horn 



