104 CONTRIBUTIONS 



with a large spiral groove. On some of the whorls the line 

 of growth may be indistinctly seen. 



P. guttula. Plate 4. Fig. 86. 



Description. Shell subovate, truncate at top, smooth ; 

 substance of the shell rather thin ; apex truncate ; suture 

 linear ; whorls four, flattened above ; mouth subovate, 

 acutely angular above, about two fifths the length of the 

 shell ; columella slightly incurved at base ; margin thick- 

 ened on the superior part, closing up a small portion of the 

 mouth. 



Length nearly .1, Breadth l-20th, of an inch. 



The smaller figure is of the size of nature. 



Observations. A single perfect specimen only of this 

 curious little species has been observed by me. It is close- 

 ly allied to the Claibornensis, but differs in the mouth, in 

 the flatness of the whorls and the truncation of the apex. 



P. Claibornensis. Plate 4. Fig. 87. 



Description. Shell subovate, smooth ; substance of the 

 shell very thick ; apex obtuse ; suture impressed ; whorls 

 four, rounded ; mouth small, subangular above, one third 

 the length of the shell ; columella thickened ; margin 

 very much thickened on the superior part, closing up a 

 large portion of the mouth. 



Length .2, Breadth .1, of an inch. 



Observations. A single specimen, the mouth of which 



