Catalogue of Land and Fresh Water Shells. 



Family Limn^:id/E. 



Sub-family LimN/EINve. 



GENUS LIMNAEA. 



Spire elevated and shell of pale dirty color. 



64. Limnaea (Radix) columella, Say. 

 H. 7-16, very variable. 



65. Limnaea (Limnophysa) humilis, Say. 

 H. 5-16, Like No. 67, but smaller. 



66. Limnaea (Limnophysi) reflexa, Say. 

 H. largest found in this vicinity. 



67. Limnaea (Limnophysa) decidiosa, Say, 65. 

 H. 9-16, brownish, facets on body white. 



68. Physa heterostropha, Say, 69, 70. 

 Shell reversed, glassy surface. 



69. Physa ancillaria, Say. 



Larger than No. 68, spire shorter. 



70. Physa gyrina, Say. 



Larger than No. 68, longer shell and spire. 



71. Planorbis (Helisoma) trivolvis, Say, 72, 73, 74. 



VV. 5-6, Disk shape, concave on upper and lower sides. 



72 Planorbis (Helisoma) bicarinatus, Say, 74. 

 Like No. 71, but sharply carinate. 



73. Planorbis glabrus, Say. 

 Larger than No. 71 and flatter. 



74. Planorbis lentus, Say. 



Like No. 72 but carinate only on upper side. 



75. Planorbis (Gyrulus) parvus, Say. 

 Small, broadly concave on underside. 



Genus Segmentina. 



76. Segmentina armigera, Say. 



W. 5-16, six white teeth far within the throat. 



Genus Physa. 



Sub-family Planorbin^e. 



GENUS PLANORBIS. 



