HANNIBAL: CALIFORNIAN PKKSHWATKR MOLLTJSCA. 163 



aperture sinuate and retracted below, umbilicus regularly broadly 

 funicular, the margin keeled ; habitat lakes and clear streams. 



Klaniatb, Nevada, and locally in Coast llange Systems. 



Quaternary : Lahontan Lake beds, Nevada ; Christmas and Summer 

 Lake beds, Oregon ; Owens Lake beds, California. 



PoMPnoLYx (Carinifex) Binneyi (Meek). 



Cariiiifex {Vorticifex) Binneyi, Meek, 1870; C. 7^/'yon?, Meek, 1870; 

 C. Tryoni, var. concava, Meek, 1870. 



Shell very large, whorls deep, planulate above, the margin sub- 

 angular, umbilicus broadly funicular, the margin angular, aperture 

 retracted below ; habitat apparently lacustrine. 



Eocene : Truckee Lake beds, Nevada ; Payette Lake beds, Idaho. 



PoMPHOLTX (Carinifex) SANCTiECLAE^E (Hannibal). 

 PI. VI, Figs. Ua-b. 

 Carinifex Sanctceclar^, Hannibal, 1909; C. Marshalli, Arnold, 1910. 



Shell small or of moderate size, spire somewhat elevated, whorls 

 not deep, coronate at suture, the upper surface concave, superior 

 margin rounded, umbilicus moderately broad and regularly funicular, 

 the margin acutely angular, aperture retracted below ; habitat 

 apparently lacustrine. 



Pliocene : Santa Clara and Kettleman Lake beds, California. 



Family PHYSID^, Dall, 1871. 



Shell small, oliviform, sinistral, columella variable, simple or 

 plicate, imperforate or sub-umbilicate ; animal sinistral, hermaphroditic, 

 tentacles filiform, buccal plate without accessory lateral jaws, foot 

 elongate-trigonal; habitat aquatic situations. 



The American Physidse have been variously maltreated and mutilated, 

 and from a dozen to over a hundred and fifty nominal species recognized, 

 depending on tlie author. Two years ago, after an examination of 

 several thousand specimens, the writer expressed the opinion ' that the 

 entire aggregation was reducible to three forms — Aplexa hypnorum, 

 Physa heterostropha, and P. heterostropha osmlans. Wider experience 

 has proved the correctness of the position taken at that time, and 

 it only remains to untangle the nomenclature and return to first 

 principles. 



Bulla hypnorum, of Linne, has been generally separated generically 

 as Aplexa from B. fontinalis, the type of Physa, on the basis of a more 

 polislied shell, absence of mantle-digitations expanded across the 

 columella, and the dentition. The dentition, however, differs chiefly 

 in the development of the teeth, for the fundamental type is essentially 

 the same ; the mantle-fingers, while nearly always present m fontinalis, 

 vary widely in number and grouping, and cannot be regarded as verj" 

 essential in generic discrimination, and, in lieu of other characters, the 

 elevation of the spire and polish of the shell must be considered as of 

 no more than sj)ecific value. Furthermore, the early stages indicate 



^ West Coast Shells, 1910, p. 312. 



