426 The Molluscan Family Planorbidae 



PLATE 95 



Shells of Planorbidae 



1-5. Helisoma amnion (Gould). Mountain Lake near San Francisco, California. 



Immature form. B3288. 

 6-9. Helisoma amnion (Gould). Clear Lake, California. Stages of growth. U.M., 81743. 

 10,11. Helisoma avimon (Gould). Clear Lake, California. LT.M., 81752. 

 12-14. Helisoma ammon (Gould). Watsonville, Santa Cruz Co., California. LT.M., 



81747. 



15. Helisoma ammon (Gould). Kern Lake, Tulare Co., California. Cooper Coll., 



B9124. 



16. Helisoma ammon (Gould). Point Happy, Indio, California. U.I., Z35624. 



17-19. Helisoma traskii (Lea). Bakersfield, Kern Co., California. Immature. U.M., 



81754. 

 20,21. Helisoma traskii (Lea). Kern Lake, Tulare Co., California. Type of Lea, figured 



by Binney, 188. Lea Coll., U.S.N.M., 121000. 

 22. Helisoma traskii (Lea). California? U.S.N.M., 47616. . 

 23-25. Helisoma traskii (Lea). Bucna Vista Canal, draining Buena Vista Lake, which 



drained Kern Lake, California. More depres.sed than Lea's type. B3066. 



All figures are enlarged about P/i' diameters 



