334 The Molluscan Family Planorbidae 



PLATE 49 



Jaws of Planorbidae 



1. Helisoma anceps (Menke). Chetek Lake, Wisconsin. 



2. Helisoma trivolvis (Say). Devils Lake, Wisconsin. Small fig. indicates striation. 



3. Helisoma truncatum (Miles). Oshkosh, Lake Winnebago, Wisconsin. 



4. Helisoma scalare (Jay). Lake Butler, Florida. 



5. Helisoma pilsbryi (F. C. Baker). Chetek Lake, Wisconsin. 



6. Helisoma oregojiense (Tryon). Tooele Co., Utah. 



7. Helisoma subcrenatum (P. P. Carpenter). Gypsum, Colorado. Superior jaw. 



8. H. pilsbryi injracarinatum F. C. Baker. Rideau River, Ontario. Superior jaw. 



9. Helisoma horni (Tryon). Paul Lake, British Columbia. 



10. Helisoma plexatum (Ingersoll). Grand Mesa, Colorado. Superior jaw. 

 IL H. campanulatum smithi (F. C. Baker). Douglas Lake, Michigan. 



12. Helisoma traskii (Lea). Outlet of Kern Lake, California. Superior jaw. 



13. Helisoma occidentale (Cooper). Klamath Lake, Oregon. Superior jaw. 



14. H. duryi normale Pilsbry. Forty miles west of Miami, Florida. Superior jaw. 



15. Helisoma corpulentum (Say). Bamiji Lake, Ontario, Canada. 



16. Helisoma magnificum (Pilsbry). Near Wilmington, North Carolina. 



17. Carinifex jacksonejisis J. Henderson. Jackson Lake, Wyoming. Jaw and cartilage 



from the side. 



18. Carinifex jacksonensis J. Henderson. Jaw from above. 



19. Carinifex ponsonbyi E. A. Smith. Klamath Lake, Oregon. Jaw and cartilage from 



below. 



20. Helisoma campatudatum smithi (F. C. Baker). Douglas Lake, Michigan. Vertical 



striation on jaw. Highly magnified. 



Line at right of fig. 1 indicates 1 mm. in length. Line at lower extreme left is 



for figs. 18 and 19 and represents 0.5 mm. in length. Middle line is 



for fig. 6. Line at right is for figs. 2, 3, 4, 5, and 



7 to 16. Figure 17 is diagrammatic. 



