162 PROCEEDINGS OF THE MALACOLOGICAL SOCIETY. 



one or more genera and sub-genera. With a limited series at band it 

 migbt be possible to make such distinctions conscientiously, but the 

 species vary so widely, and individuals of one so closely approach some 

 other except for some apparently trivial character, tbat the writer 

 has felt obliged to reduce the classification to as compact a form as 

 possible. 



Tbe reference of the Baikalian Choanomphalus to this group, first 

 suggested with doubt forty years ago when that genus was unknown 

 anatomically, has been taken up and treated as established in spite of 

 the fact that Dybowski some years later pointed out that it possesses 

 a truly Planorboid radula. 



Genus Pompholtx, Lea. 



Pom/pholyx, Lea, 1856 (P. cffusa, Lea) ; Fompholopsis, Call, 1888 

 {Pompholopsi's JFhitei, Call = P. effusa, Lea, syntonic form). 

 Type, Pompholyx cjfusa. Lea. 



Sub-genus Carinifex, Einney. 



Planorhis (sp.). Lea, 1858 {Planorhis Ncwlcrryi, Lea) ; Carinifex, 

 Binney, 1865 {P. Newberry i, Lea); Meciamjdropha, Lea, 1866 

 [P. Newherryi, Lea) ; Vorticifex, Meek, 1870 (^Carinifex Binneyi, 

 Meek). 

 Type, Planorhis Newherryi, Lea. 



Sub-genus Pompholyx, s.s. Shell of moderate size, averaging 8 mm. 

 in diameter, velutiniform, imperforate or sub-perforate, spire but 

 slightly elevated, aperture expanded ; habitat lakes and clear streams. 

 Huh-^enns Carinifex. Shell similar to precedingbut sub-planorbiform, 

 whorls usually more or less angular, concave above the periphery, 

 which is superior, sloping inward below to a broad more or less 

 funicular umbilicus, spire but little elevated, aperture rather trigonal, 

 broader above ; Pompholyx stage carried b;ick to very earl}' adolescence ; 

 habitat lakes and clear streams. 



Pompholyx effusa, Lea. 



P. effusa, Lea, 1856; P. solida, Dall, 1870; Pompholopsis Whitei, 

 Call, 1888 (syntonic form); Pompholyx Leana, II. & A. Adams, 

 fide Dall, 1870. 

 Shell as in sub-genus, whorls moderatelj' deep ; habitat lakes and 

 clear streams. 



Klamath, Nevada, Mojave, and Coast Ilange (locally) Systems. 

 Quaternary: Lahontan Lake beds, Nevada; Owens Lake beds and 

 playa deposits of Mojave Desert, California ; Christmas and Summer 

 Lake beds, Oregon. Pliocene : Santa Clara Lake beds, California. 



Pompholyx (Carinifex) Newbekryi (Lea). 



Planorhis Newherryi, Lea, 1858; Carinifex Breweri, ' Newcomb MS.,' 

 Einney, 1865 (nude name); C. Neivherryi, var. tninor, J. G. 

 Cooper, 1870; C. Ponsonhyi, E. A. Smith, 1875. 

 Shell largo, spire but little elevated, whorls dcu'p, nearly ])l;iTnilat,(', 



and sliglitly concave above with a more or less distinct marginal keel, 



