360 The Molluscan Family Planorbidae 



PLATE 62 



Radiilae of Helisoma 



See remarks on plate 53. Line at lower right of plate 

 indicates 25 microns in length. 



L Helisoma campanulatum (Say). Oneida Lake, New York. 



60, center tooth; 1-7, lateral teeth; 8, 9, intermediate teeth; 10-20, marginal teeth. 



2. Helisoma campanulatum. wisconsincnse (Winslow). Little Arbor Vitae Lake, Wis- 



consin. 

 50, center tooth; 1-8, lateral teeth; 9, 10, intermediate teeth; 11-15, marginal teeth. 



3. Helisoma campanulatum canadcnse F. C. Baker. Bamiji Lake, Ontario, Canada. 



52, center tooth; 1-8, lateral teeth; 9, 10, intermediate teeth; 11-20, marginal teeth. 



4. Helisoma campanulatum smithi (F. C. Baker). Douglas Lake, Michigan. 



60, center tooth; 1-8, lateral teeth; 9, 10, intermediate teeth; 11-19, marginal teeth. 



