54 



AMERICAN JOURNAL 



8. Triodopsis loricata, Gould. 



Plate 9. figures 16, 19. 



Shell small, orbicularly depressed ; spire convex, not much 

 elevated, suture well impressed ; whorls 5, convex, thin, ob- 

 liquely striate, with small epidermal scales or scars, and in fresh 

 specimens hispid, very much contracted behind the lip ; aperture 

 transversely trilobate, the very oblique parietal tooth quite 

 small, and the two lip teeth merely slight elevations of the sur- 

 face ; base very convex, umbilicus narrow and deep, slightly 

 circumscribed by the lip. Dark horn color. 



Diam. 6, height 4 mill. 



" 8, " 5 " (var. major. 



California. 



In general appearance this shell is singularly allied to Steno- 

 trema monodon ; it is distinguished principally by the small, 

 scarcely-developed lip teeth, and by its geographical distribu- 

 tion. The roughened appearance of the epidermis, as it gener- 

 ally exists when denuded of hairs, being the scars of their 

 insertion, is another link connecting this with Stenotrema. 



ISOGNOMOSTOMA, Fitzinger. 



This genus has for its type Helix personata of Lamarck, a 

 common European shell, with which the two following species 

 are closely allied. The shells are more elevated, and revolve 

 more closely than in Triodopsis, appearing, when viewed from 

 above, to be very like Stenotrema. The umbilicus is covered in 

 this, differing from the last genus, as well as by the generally 

 smaller size. 



1. Isognomostoma inflecta, Say. 



Plate 9, figure 10. 



Shell depressed, convex ; spire slightly raised, suture not 

 deep; whorls 5, minutely obliquely striate, sometimes hirsute, 

 very much contracted behind the lip; aperture trilobed, parietal 

 tooth almost transverse, large and blade-shaped, basal lip tooth 

 a small upright tubercle, upper lip tooth in the middle of the 



