374 The Molluscan Family Plariorbidae 



PLATE 69 



Radulae of Planorbidae 



See remarks on plate 53. Lines near figs. 1 to 5 indicate 25 microns in 

 length; lines near figs. 6 to 9 indicate 10 microns in length. 



1. Gyraulus hirsutus (Govild). Lake Nipissing, Ontario, Canada. 



50, center tooth; 1, lateral tooth; 9, 11, intermediate teeth; 12-16, marginal teeth. 



2. Gyraulus deflectus obliquus (DeKay). Taylor Lake, Quebec, Canada. 



60, center tooth; 1, lateral tooth; 9-11, intermediate teeth; 13-18, marginal teeth. 



3. Gyraulus parvus (Say). Winnebago Lake, near Oshkosh, Wisconsin. 



55, center tooth; 1, 5, lateral teeth; 6, intermediate tooth; 7-10, marginal teeth. 



4. Gyraulus similaris (F. C. Baker). Tolland, Colorado. 



60, center tooth; 1, 6, lateral teeth; 8, 10. intermediate teeth; 13, 15, marginal 

 teeth. 



5. Gyraulus vermicularis (Gould). Near San Francisco, California. 



50, center tooth; 1-6, lateral teeth; 7-10, intermediate teeth; 11, marginal tooth. 



6. Armiger imbricatus (Miiller). Michigan. 



55. center tooth; 1-6, lateral teeth; 8, 10, intermediate teeth; 12, 13, marginal 

 teeth. 



7. Segmentina nitida (Miiller). Near War.saw, Poland. 



60, center tooth; 1-8, lateral teeth; 13-16, marginal teeth. 



8. Polypylis calathus (Benson). North Shan State, Burma. 



50, center tooth; 1-8, lateral teeth; 13-18, marginal teeth. 



9. Intha capitis Annandale. North Shan State, Burma. 



60, center tooth; 1-8, lateral teeth; 11, 12, marginal teeth. 



