508 The Molluscan Family Planorbidae 



PLATE 136 



Shells of Planorbidae 



1-3. Gyraidus albus (Miiller). Scaly Beck, near Scarborough, England. No. 3 shows 



fine spiral sculpture. Baker coll., 2768. 

 4-7. Gyraulus hirsutus (Gould). Lynnfield, Massachusetts. M.C.Z., 34915. 

 8-10. Gyrmdus hirsidus (Gould). Lynnfield, Massachusetts. M.C.Z., 34915. 



11. Gyraulus hirsutus (Gould). Lynnfield, Massachusetts. Base of shell showing 



rounded whorls. M.C.Z., 34915. 



12. Gyraidus hirsutus (Gould). Lynnfield, Massachusetts. Hirsute shell showing larger 



and less numerous rows than in albus, fig. 3. 



13-15. Gyraulus deflectus (Say). Miller Bay, Lake Winnebago, Wisconsin. Baker Coll., 



2036. 

 16,17. Gyraulus deflectus (Say). Lake Maxinkuckee, Indiana. Baker Coll., 127. 

 18-20. Gyraulus deflectus (Say). Miller Bay, Lake Winnebago, Wisconsin. Baker Coll. 



2036. 



21. Gyraulus deflectus (Say). Harbor Island. Lake George, New York. L^S.X.M., 



426560. Showing hirsute periostracum. 



22. Gyraulus deflectus obliquus (DeKay). Okoboji Lake. Iowa. Showing hirsute 



epidermis. U.S.N.M., 525319. 



23. Gyraulus deflectus (Say). Lake Maxinkuckee, Indiana. Immature specimen with 



hairy periostracum. Baker Coll., 127. 



24. Gyraulus deflectus (Say). Harbor Island, Lake George, New York. Specimen with 



very acute periphery and hairy periostracum. U.S.N.M., 426560. 

 25,26. Gyrardms deflectus (Say). Lake Maxinkuckee, Indiana. Immature. Baker 

 Coll., 127. 



27-31. Gyraulus deflectus obliciuus (DeKay). Round Pond, Charlotte, near Rochester, 



New York. Baker Coll., 1120. 

 32-37. Gyraulus borealis (Westerhmd). Tanana River, Chena, Alaska. U.S.N.M., 



193289. 



38. Gyraulus borealis (We.sterlund). Popoff Island, Shumigins Group, Alaska. 



U.S.N.M., 180292. 



39. Gyraulms borealis (Westerlund). Saigan, Siberia. From Zool. Mus. Russia. Named 



by Westerlund. U.S.N.M., 15248. 



All specimens are enlarged four diameters 



