[90 J 



This species is introduced to show that a form very closely 

 allied to our own shells, inhabits a far-distant locality. Probably 

 the intermediate country of Mexico contains undiscovered species 

 exhibiting the same characteristics. The spire is represented 

 too much elevated in the figure. 



6. Triodopsis vultuosa, Gould. 



Plate 9, figure 14. 



Shell globosely depressed, closely delicately striate, rather 

 «olid; spire convex, not much elevated, suture well impressed; 

 whorls 5J, convex, slowly increasing, the last subangular, and 

 ■deflected at the aperture, well rounded below, with a moderate 

 umbilicus ; aperture lunate, its outline somewhat sinuous, parietal 

 "tooth a broad lamina, oblique, joined to the lip below, lower lip 

 i;ooth small, upper lip tooth expanded and reflexed. Dark horn 

 <color. 



Diam. 10, height 5 mill. 



Texas. 



Intermediate between M. fallax and H. Texasiana. 



7. Triodopsis Mullani, Bland and Cooper. 



Plate 9, figure 15. 



Shell globosely depressed, irregularly striate, shining, with a 

 lihin epidermis, covered with minute spiral lines and tubercles, 

 .(the latter probably the scars of hairs) ; whorls 6, convex, much 

 ■constricted behind the aperture, and smoother on the 'base; 

 aperture trilobate, parietal tooth small, linguiform, lower lip 

 itooth lamelliform, upper one small, and sometimes obsolete ; um- 

 bilicus moderate, partially covered by the lip. Dark horn color. 



Diam. 13-5, height 7 mill. 



Washington Territory and Oregon. 



Darker in color, with smaller umbilicus and difl"erently formed 

 iteeth from tridentata. 



