May, 1893.] MOLLUSKS OF THE DEATH VALLEY EXPEDITION. 277 



up to the usual adult mean. Stephens' specimens are all of one size, 

 under rather than up to the average mean of adults, and of that per- 

 plexing aspect so frequently exhibited in the fresh-water snails, 

 that make the use of one specific name instead of another simply an 

 arbitrary matter. They would pass as subspecies of the above, or 

 (jyrina. The numerous examples were detected at Moran's, near Ben- 

 ton, Calif., at an altitude of 5,000 feet. Bailey's Panamint Hot Springs 

 specimens are hardly more characteristic ; they point suggestively to 

 the humerosa form, of the Colorado desert. Lloyd's two Texas exam- 

 ples are dark amber colored and rather solid shells. 



Carinifex newberryi Lea. 



Keeler, Inyo County, Calif. (Mus. No. 123620), T. S. Palmer. 



Numerous examples, in a bleached and semi-fossilized condition. 

 These exhibit, as is not unusual with this form, considerable \ ariation. 

 As additional information comes to us from time to time, the great 

 range of this species, first detected by Dr. J. S. Newberry, in the 

 Klamath Lake region of northern California, near the Oregon line, and 

 described by Dr. Lea in 1858, becomes exceedingly instructive and 

 interesting. Hemphill collected it livin g in the neighborhood of Keeler, 

 which is near the margin of Owens Lake, several years ago. Dr. 

 Edward Palmer obtained it in Utah Territory, near Utah Lake, in the 

 Wahsatch Mountains, and it has been found in the Tertiaries of 

 Nevada (King's Survey). ." In the Lahontan Basin it ranges from the 

 shores of Walker's Lake, north to Button's Ranch, Christmas Lakes, 

 Oregon, where it is found semi-fossil" [Call]. Utah Lake is the east- 

 ernmost locality as yet known. 



Order PROSOBEANCHIATA. 

 Suborder PECTINIBRANCEIATA. 

 Section Taenioglossa. 

 Amnicola micrococcus Pilsbry, sp. nov. 



Shell minute, globose, with short conic spine and narrow umbilicus. 

 Whorls 3|, convex, especially below the sutures, the apex 

 very obtuse. Surface smooth, light olive colored. Aper- 

 ture ovate, about half the length of the entire shell, bluntly 

 angled above; the inner lip is either free from the preced- 

 ing whorl, or in contact only at the upper part. Alt. 1.5, 

 diam. 1.3 mm . 



Fi£j. 1. Amnicola 



A smaller species than A. granum Say, with oval instead micrococcus. 

 of round aperture and shorter spire. 



Type from small spring in Oasis Valley, Nevada (Mus. No. 123622), Dr. C. Hart 

 Merriam, June, 1891. Collected also in Death Valley by Nelson and Bailey, Feb- 

 ruary 4, 1891 (MUs. No. 123904). 



Several examples of this quite minute shell were detected in a small 

 spring. This is a form not heretofore observed and an exceedingly 



