162 



PROCEEDINGS OF THE ACADEMY OF 



[March, 



Lymnaea bulimoides cockerelli n. subsp. Figs. 13-17. 



Shell subglobose, pale yellowish-corneous, composed of 4^ convex 

 whorls which are finely striate but without spiral lines or malleation. 

 Spire very short, last whorl and aperture very large. Aperture short- 

 ovate, its length three-fifths to two-thirds that of the shell. Columella 

 broadly expanded, not folded. Umbilicus large. 



Fig. 13. 



Fig. 14 



Fig. 16. 



Fig. 17. 



New Mexico: Las Vegas (type locality. Miss Mary Cooper), and in the 

 charcoal zone of the Pleistocene of Arroyo Pecos (T. D. A. Cockerell) ; 

 near Farmington (George H. Pepper) ; Acama (Dr. E. Palmer). Colorado : 

 Pool southeast of Denver (J. D. Putnam). Nebraska: Ogalalla (C. T. 

 Simpson). Dakota: Lake Hermann (P. C. Truman). 



Fig. 18. 



Fig. 19. 



This form differs from L. bulimoides and L. techeUa by its more glo- 

 hose shape and shorter spire, and so far as we have seen is readily separ- 

 able from both. Figs. 13-15 represent the types from Las Vegas ; 16, 17 

 are larger shells from Farmington, sent by Mr. George H. Clapp. 



L. hiilimoides sonomaensis Hemphill , from Sonoma county, California , 

 approaches cockerelli, but differs by the more rapidly expanding last 



