Perkins.] 134 [October 6, 



dilatatus Gould, Invert. Mass., p. 210, fig. 140; Hald., Monogr., p. 

 23, pi. iv, figs. 15-18; De Kay, Moll. N. Y., p. 66. 



I have found this nowhere except in a small pond on "Whitney 

 Avenue, three quarters of a mile north of the city. 



Gyraulus hirsutus Morse, Journ. Port. Soc. Nat. Hist., Vol. i, 

 p. 41. G/jraulus alius Binney, Shells of N. A., pt. n, p. 132, figs. 

 219-221. Planorbis hirsutus Gould, Invert. Mass., p. 206, fig. 135; 

 De Kay, Moll. N. Y., p. 64. Planorbis alius Hald., Monogr., p. 29, 

 pi. iv, figs. 8-10. 



Common everywhere. 



Gyraulus parvus Morse, Journ. Port. Soc. Nat. Hist., Vol. I, 

 p. 41; Binney, Shells of N. A., pt. n, p. 133, figs. 222-224. Planor- 

 lis parvus Say, Am. Conch., p. 45, pi. lxxix, fig. 5, 1816; Hald., 

 Monogr., p. 27, pi. iv, figs. 19-23; Gould, Invert. Mass., p. 209, fig. 

 139 ; De Kay, Moll. N. Y., p. 66. 



Common everywhere. 



Plaxorbula Hald., 1842. 



Planorbula armigera Morse, Journ. Port. Soc. Nat. Hist., Vol. 

 i, p. 40 ; Binney, Shells of N. A., pt. n, p. 137, fig. 229. Planorlis 

 armigerus Say, Am. Conch., pp. 66, 129, 1821; Hald., Monogr., p. 

 .30, pi. iv, figs. 11-15; Gould, Invert. Mass., p. 205, fig. 138 ; De Kay, 

 Moll. N. Y., p. 62, pi. iv, fig. 64. 



Not very common. 



Physa Drap., 1807. 



Physa ancillaria Say, Am. Conch., p. 114, 1825; Gould, In- 

 vert. Mass., p. 212, fig. 142; Hald., Monogr., p. 27, pi. iii, figs. 1-10; 

 Binney, Shells of N. A., pt. n, p. 81, fig. 139. Physa olesa De Kay, 

 Moll. N. Y., p. 78, pi. v, fig. 86. 



Not very abundant. 



Physa heterostropha Say, Am. Conch., pp. 68, 130, pi. lxix, 

 fig. 6, 1821 ; Gould, Invert. Mass., p. 211, fig. 141; Hald., Monogr., 

 p. 23, pis. i, ii, figs. 1-9. 



Common in all streams and many ponds. 



Bulinus Adanson, 1757. 



Bulinus hypnorum Binney, Shells of N. A., pt. n, p. 99, fig. 

 170. Physa hypnorum (Linne) Hald., Monogr., p. 36, pi. v, figs. 4-9 ; 



