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THE CHICAGO ACADEMY OF SCIENCES. 



provided with swellings at regular intervals, which support a 

 number of sharp spines pointing toward the aperture; on the 

 columella there is also a smooth, heavy, revolving rib; on 

 the base of the shell, placed far within the aperture, are two 

 smooth, heavy lamellae which extend only about a third of a 

 volution; the parietal lamellae are more or less granular in 

 texture; peristome narrowly reflected, slighty thickened, the 

 terminations widely separated; umbilicus narrow, open (Figs. 

 58. 59)- 



Fig. 58. 



STROBILOPS LABYRINTHICA Say. 

 showing parietal lamellae. (Binney. 

 Fig. 282.) 



Fig. 59. 



STROBILOPS LABYRINTHICA Say. 

 Parietal lamellae enlarged. (Binney, 

 Fig. 283.) 



Greater diameter, 2.15; lesser, 2.00; height, 1.50 mill. (11994.) 

 2.15; " 2.00; " 1.60 " (11994.) 



Animal: Very small; foot rather short, narrow, rounded 

 beforehand behind; color white on the foot and sides of body 

 and jet black on head, neck and eye-peduncles; the head is 

 rather broad and the eye-peduncles are short, very thick and 



Fig. 60. 



Radula of STROBILOPS LABYRINTHICA Say. (Original.) c, central 

 tooth; 1, first lateral; 5, intermediate lateral; 10, fifth marginal; J, jaw. 



bulbous at their end, where the eyes are situated; the tentacles 

 are very short and thick. 



Jaw: Long and narrow, somewhat arched, ends blunt; 



