284 A MANUAL OF AMERICAN LAND SHELLS. 



inner, lower, lateral expansion of the base of attachraert and tlie inner 

 side cusp, with its cuttingpoint. The transition teeth are characterized by 

 the gradual lesser proportional development of the reflection and greater 

 development of the inner cutting point. As the teeth pass outward, this 

 pont becomes bifid, the reflection becomes gradually shorter, until the 

 true marginals are reached. These last are low, wide, the reflection 

 equaling the base of attachment, the inner cutting point being greatly 

 developed, long, oblique, bluntly bifid, and the inner bifurcation the 

 shorter of the two ; the outer cusp is very short, blunt, sometimes al*o 

 bifid. In this species the tenth is the first lateral showing decided modi- 

 fication ; the fourteenth tooth has its inner point bifid ; the seventeenth 

 tootli is a decided marginal. The transition from laterals to marginals is 

 so gradual that it is often dififlcult to give the number of perfect laterals. 

 In many cases, therefore, the number given by me must be considered as 

 only approximately correct* There is great variation in the denticulation 

 of the marginal teeth. The general character of the dentition of the 

 other species is about the same as in appressa. I found great difficulty 

 in detecting the side cutting points in several species, especially triden- 

 tata and paUiata. In some species I did not find the transition teeth 

 or inner marginals with bifid cutting point. Eelix personata is the 

 only European species of this subgenus, but no figure of its dentition 

 has been published to compare with that of our species. The same is 

 true of the two Central American species known. 



Triodopsis palliata, Say. 



Shell with the umbilicus closed, thin, depressed; epidermis dark 

 Fifi. 303. brown or chestnut-color and rough with minute, acute 

 projections and stiff hairs ; whorls 5, flattened above and 

 rounded below, with numerous very fine, oblique strife; 

 ai>erture three-lobed, much contracted by the peristome 

 and teeth ; peristome white, sometimes edged with brown, 

 T.paihata. widely reflected, with two projecting teeth on the inner 

 margin, the one near its junction with the body- whorl acute and promi- 

 nent; theother, on thebasal portion, long, lamellar, andbut little ])ronii- 

 nent; parietal wall with a very prominent, white, curved tooth, ])rojoct- 

 ing nearly' perpendicularly from the shell, and forming one boundary 

 of the aperture ; umbilicus covered with a white callus, the continuation 

 of the reflected i)eristome ; base convex. Greater diameter 21, lesser 

 18™"'; height, lO""". 



