1922] NATURAL SCIENCES OF PHILADELPHIA 93 



living, 18 dead shells. Also found 1 mile south of Indian Well, 

 Riverside County, California; George Willett, March, 1919; 6 liv- 

 ing specimens. 



This very attractive little snail in many respects recalls Pilsbry's 

 description of his Micrarionta rixfordi, but the umbilicus is narrower, 

 and the sculpturing of the earlier whorls evidently quite different. 

 As the two species come from different mountain systems, with 

 the whole upper Cahuilla Basin between, it is doubtful if they 

 are as nearly allied as the descriptions superficially indicate. To 

 my notion, M. hidioensis is really the nearest akin to xerophila of 

 any of those previously described. Its larger size, more elevated 

 outline, and narrower umbilicus serve to distinguish it, but it is 

 the same general type of shell, and it may be that enough inter- 

 grades will come to light in intervening territory to reduce M. 

 xerophila to the status of a subspecies. In fact, the small series 

 of snails above noted which Mr. Willett collected to the south of 

 Indian Well may represent one of the intermediate forms, as his 

 specimens, though surely not all typical of indioensis, are yet not 

 quite characteristic of xerophila. It seems best to refer them to 

 the latter species at least tentatively, as the available information 

 regarding the possible limits of variation in all these forms is 

 still very scanty. 



The dead shells were either picked up on the surface or from 

 among loose soil and rocks, but living ones could be obtained only 

 by digging out the loose detritus in the lee of large rocks, following 

 up crevices, or turning stones. They were generally within a few 

 inches of the surface, and wherever deeper digging was attempted 

 we met with no success. 



Micrarionta indioensis (Yates 1890) 



1889. New species of Helix Orcutt, W. Am. Hoi., vol. 6, p. 96 (brief note). 



1890. Helix Carpenteri var., Yates, Nautilus, vol. 4, p. 51. 



1890. Helix (Arionta) Carpenteri var. Indioensis Yates, Nautilus, vol. 4, p. 

 63. 



1S90. Helix Traskii, form, Orcutt, Nautilus, vol. 4, p. 07. 



1891. Helix Traskii, var. Indioensis Orcutt, W. Am. Sci., vol. 7, p. 223 

 (brief note). 



1892. Helix rowellii (pars) Cooper, Zoe, vol. 3, p. 19 (brief note). 



1894. Epiphragmophora indioensis Pilsbry, Man. Conch., (2), vol. 9, p. 199 

 (teste Bartsch). 



1896. Epiphragmophora indioensis Dall, Proc. U. S. Nat. Mus., vol. 19, 

 p. 337, 366 (brief note). 



1897. Epiphragmophora indioensis Pilsbry, Nautilus, vol. 11, p. 59 (merely 

 catalogued). 



1898. Epiphragmophora indioensis Pilsbry, Cat. Am. Land Sh., p. 5 (merely 

 catalogued). 



