364 THE CHICAGO ACADEMY OF SCIENCES. 



SHELL: Large, ovate, thin; periostracum yellowish-horn; sur- 

 face with fine lines of growth crossed by equally fine spiral lines ; 

 whorls six, flatly rounded, very rapidly increasing in diameter, the last 

 whorl very large and somewhat elongated ; spire short, broadly ovately 

 conic; sutures well impressed; aperture elliptical or elongate-ovate, 

 narrowed above, longer than the spire, effuse anteriorly ; outer lip thin, 

 only slightly thickened by a longitudinal varix ; inner lip thin, narrow, 

 appressed to the umbilical region so as to leave a well marked chink; 

 callus on the parietal wall thin, wide, well marked; columella twisted, 

 with a strongly developed, ascending plait. 



Length. Width. Aperture length. Width. 



30.00 13.50 18.00 8.50 mill. Type. 



28.00 13.50 17.00 8.00 " 



31.00 14.50 18.50 9.50 " 



TYPE: The Chicago Academy of Sciences, one specimen, No. 

 23653. Cotypes : Collection Illinois State University, two specimens. 



TYPE LOCALITY: Near San Francisco, California. 



ANIMAL, JAW, RADULA and GENITALIA: Unknown. 



RANGE: California to Colorado. A race of the Transition and 

 Upper Sonoran life zones, confined to the Californian and Coloradoan 

 regions. 



RECORDS. 



CALIFORNIA: Near San Francisco, San Francisco Co. (Nason) ; San 

 Joaquin River (Mrs. E. E. Rush) ; Merced Lake, Merced Co. (Dall; Stearns). 



COLORADO: Between Anknas and La Plata rivers (Ingersoll). 



GEOLOGICAL DISTRIBUTION : Unknown. 



ECOLOGY: Not recorded. 



REMARKS: Leai seems to be a very distinct species easily rec- 

 ognized by its short spire, very large, narrow, aperture and heavy 

 columellar plait. It is more nearly related to Galba proximo, rowellii 

 Tryon than to any other Lymnaea but seems to be distinct. It has 

 probably been heretofore identified as a form of the protean species 

 palustris, but it is unquestionably distinct from any form of that 

 species. It differs from palustris in its larger and flatter body whorl, 

 long, oblique and reflexed aperture and in the form of the columella. 

 The aperture somewhat recalls reflexa. 



Specimens from Colorado, deposited by Ingersoll in the Smith- 

 sonian collection appear to belong to this species although the locali- 

 ties are widely separated. Ingersoll's record of nuttalliana from 

 Colorado "between Animas and La Plata rivers" was probably based 

 on these specimens. The species is dedicated to one of America's 

 best known pioneer conchologists, Dr. Isaac Lea. 



