414 The Molluscan Family Plwwrhidae 



PLATE 89 



Shells of Planorbidae 



1-4. Helisoma trivolvis hntum (Say). Austin, Texas. Figure 3 varies toward hiter- 



textum. U.S.N.M., 252256. 

 5,6. Helisoma trivolvis intertcxtum (Sowb.). Fort Smith, Arkansas. Variation toward 



lentum (fig. 6). U.S.N.M., 120965. 



7. Helisoma trivolvis intertextum (Sowb.). South CaroHna? Binney's fig. 179 of Pln- 



norbis glabratus (not of Say). U.S.N.M., 29219. 



8. Helisoma trivolvis intertextum (Sowb.). Leon, Texas. U.S.N .M., 28210. 



9,10. Helisoma trivolvis reticulatum (Dall) {^intertextum Say). Salt Lake, Hils- 

 borough Co., Florida. Types. U.S.N.M., 75421. 



11. Helisoma truncatum (Miles). Saginaw Bay, Michigan. Type. Binney's fig. 202. 



U.S.N.M., 9010. 



12. Pknwrbis bellus Lea (^= Helisoma trivolvis lentum (Say) ). Type. Tennessee. Lea 



Coll., U.S.X.M., 121178. 

 13-17. Helisoma kennicotti F. C. Baker. Lake Isle la Crosse, English River, Canada. 

 15, holotype; 16, 17, paratypes; 13, 14, immature. U.S.N.M., 29231 (old 9272). 



18. Helisoma subcrenatum (Cpr.). Reservoir near Flowcree, Montana. B3792. 



19. Helisoma subcrenatum (Cpr.). Wainwright Park, Alberta. U.I., Z34689. 



20. Helisoma subcrenatum {C]n\). Fort Yukon, Alaska. U.S.N .M., 218908. 



21. Helisoma subcrenatum disjecturn (Cooper). Boise, Idaho. U.I., Z36335. 



22. Helisoma subcrenatum plexatum (Ing.). Sagnache, Colorado. U.S.N.M., 535328. 



23. Helisoma occidentale (Cooper). Klamath Falls, (3regon. U.S.N.M., 219750. 



24. Helisoma occidentale (Cooper). Tule Lake, California. U.S.N.M., 160839a. 



25. Helisoma ammon (Gould). Daggett, California. U.S.N.M., 349083. 



26. Helisoma amnion (Gould). Spring Valley, San Mateo Co., California. U.M., 84105. 



27. Helisoma ammon (Gould). Clear Lake, California. U.M., 81743. 



28,29. Helisoma trivolvis (Say). Aquarium specimens raised by Dr. E. G. Berry. Note 

 resemblance to Helisoma duryi seminole. B3796. 



Figures 18-29, immature. 



All figures are enlarged a trifle less than two diameters 



