278 NORTH AMERICAN FAUNA. [No. 7. 



interesting little species. It was referred to Mr. Pilsbry for determi- 

 nation and description. 



Amnicola porata Say. 



Kelton, Utah (Mus. No. 123625), Vernon Bailey, November 7, 1891. 



Two examples in the dry clay wash about 100 feet above the lake. 



Bythinella protea Gould (Stearns). 

 = Amnicola protea Gould, 1855.* 

 = Melania exigua Conrad, 1855. 

 .= Try onia protea Binney et auct. 

 -f- Bythinella seemani Frau. (Pilsbry). 

 —Hydrobia seemani Frau. 1863. t 

 Saratoga Springs, Death Valley (Mus. No. 123905) ; January 30, 1891, F. W, Nelson; 

 February 4, 1891, Vernon Bailey. 



Several hundred living specimens were obtained at the springs by 

 Mr. Nelson and a large number in a marsh near the springs by Mr. 

 Bailey. Associated with them were a few examples of Amnicola 

 micrococcus Pilsbry before mentioned. 



In explanation of tlie foregoing synonymy it should be stated that 

 Bythinella protect is a,n exceedingly variable form, including examples 

 that have a perfectly smooth surface, and others that are variously 

 sculptured. In all, whether sculptured or otherwise, the apex whorls 

 are smooth. The smooth form, like those referred to below, has the ap- 

 pearance in every respect of an attenuated, slender drawn out Bythinella, 

 like nicldiniana, described by the late Dr. Lea in 1839, and it, protea, 

 may ultimately be regarded as belonging to Lea's species. 



B. seemani as identified by Mr. Pilsbry appears to be the smooth 

 variety or aspect of Gould's Tryonia protea (=Melania exigua Conrad). 



Frauenfeld's description is based upon examples from Durango, Mex- 

 ico. The National Museum contains a number of specimens from 

 Andocutira in the State of Michoacan, Mexico, from the bed of an 

 ancient lake. These latter are no doubt the same as the Durango 

 shells; they are perfectly smooth, of a porcellaneous whiteness and 

 texture, and in no way different from the smooth form of B. protea, with 

 which they have been repeatedly and carefully compared. The Mich- 

 oacan region is nearly 1,800 miles south of the Colorado desert. 



The granulose form or variety agreeing with figs. 141 and 142 of 

 Binney,f was detected near the line of the Southern Pacific Bailroad in 

 June, 1888, by Mr. C. B. Orcutt, of San Diego. He found them living 

 in pools at Indian or Fish Springs, some!5 miles northwest of the station 

 on said road, known as Salton. The pools, of which there are several, 

 varying from 10 to 20 feet across, are situated at the base of the San 

 Jacinto range of mountains. They are only a few feet deep and are 



* Pacific Railroad Reports, v, 1855, p. 332. 



t Verhandlungen der k. k. zoologisch-botanischen Gesellschaft in Wien, Jahr- 

 gang 1863, p. 1025. 



tSee Land and Fresh Water Shells of North America, Smithsonian Misc. Collec- 

 tions 144, Sept. 1865, p. 72. 



