TMK NAirrii.i s. 99 



these riblets to collect. Only a good lens reveals this sculpture, and 

 in specimens which have been collected dead, or cleaned l>y ordinary 

 methods, it is usually lost. Still, a snflicicntly patient examination 

 will srenerally show some trace of it somewhere on most specimens'. 

 77/t/s. conspurcateUa, of eastern Mexico, the type of the genus, has 

 similar euticular riblets, but they are more widely spaced and rather 

 more persistent. 



In young; and half-grown shells, if perfectly preserved, the riblels 

 bear rather sparsely scattered and long hairs, very delicate and easily 

 rubbed oil'. I do not know that adults ever retain them ; though in 

 several Mexican species such hairs occur on the full-grown shell, and 

 many AVest Indian species hear close bristles. 



The foregoing observations are based upon the entire series of 

 specimens in the collection of Mr. E. H. Ashmun, which he most 

 liberally sent me for examination, and those in the collection of the 

 Academy, including Gabb's types. 



The published figures and descriptions of this species leave much 

 to be desired. Gabb gives quite a good description, though none of 

 his specimens show 4*, whorls, as he states. The dimensions, 

 "height .<>!>, greatest diam. .lf>. smallest diam. .13 inch " == 2^, 4, 

 3^ mm., are in a rough way accurate. The figures are had. 



Binney's figures (Man. Amer. L. Sh., p. 169, fig. 1;V.() are too 

 narrowly umbilicated, the spire is too conic, and the terminations of 

 the lip do not approach enough. Moreover, they do not indicate the 

 surface-sculpture. The whorls are described as " scarcely convex ' 

 whereas they are unusually so ; the ends of the peristome are said to 

 be "hardly approaching" while they actually converge so as to 

 nearly meet in adult shells. The dimensions, " greater diam. 4, les- 

 ser 3^, height 1 mm." are erroneous, the largest in Gabb's type lot 

 measuring 4 mm. in greatest, .>.f> in least diameter, u'ft/t a licujlit of 

 2.6 mm. An adult specimen from Jerome, Arizona, collected by 

 Mr. Ashmun, measures : diam. 3.o, alt. 2.3 mm. 



Gabb's types were from "Fort Grant, at the junction of the Ari- 

 vapa and San Pedro rivers," in Graham Co., southeastern Arixona. 



Mr. Ashmun has collected specimens in the following localities: 

 Jerome, Patagonia Mts., Crittenden, Prescott and Nogales, Arizona, 

 and Cook's, New Mexico. The International Boundary Commis- 

 sion collected hornii at the summit of Hachita Grande Mt., Grant Co., 

 N. M., and Dall mentions seeing the species from the drift of the 

 Yaqui River, Mexico. No other localities are known for the species. 



