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 1-20th, 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 elose- 
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 
