Contents xv 



VII. Systematic Account of the Subfamilies — continued 



Subfamily Segmentininae F. C. Baker, New Subfamily — continued 



Genus Pingiella F. C. Baker, New Genus 109 



Genus Intha Annanclale, 1922 112 



Genus Drepanotrema Fischer and Crosse, 1880 114 



Subgenus Drepanotrema SS 118 



Subgenus Fossulorbis Pilsbry, 1934 118 



Genus Paraplanorbis Hanna, 1922 119 



Genus Platytaphius Pilsbry, 1924 120 



Genus Acrorbis Odhner, 1937 121 



Subfamily Helisomatinae F. C. Baker, 1928 123 



Genus Helisoma Swainson, 1840 123 



Subgenus Helisoma SS 124 



Subgenus Seminolina Pilsbry, 1934 129 



Subgenus Pierosoma Dall, 1905 134 



Subgenus Planorbella Haldeman, 1842 150 



Genus Carinifex ^Y. G. Binney, 1863 154 



Genus Vorticifex :Meek, 1870 159 



Genus Perrinilla Hannibal, 1912 160 



Genus Parapholyx Hanna, 1922 161 



Genus Pompholopsis Call, 1888 165 



Genus Planorbarius Froriep, 1806 166 



Subfamily Planorbulinae Pilsbry, 1934 172 



Genus Planorbula Haldeman, 1840 172 



Subgenus Planorbula SS 173 



Subgenus Haldemanina Dall, 1905 177 



Genus Promenetus F. C. Baker, 1935 178 



Genus Menetus H. and A. Adams, 1855 182 



Subgenus ^lenetus SS 183 



Subgenus ]\Iicromenetus F. C. Baker, New Subgenus . 187 



Genus Planorbifex Pilsbry, 1934 190 



VIII. Groups of Uncertain Affinities 192 



Subfamily Choanomphalinae Germain, 1923 192 



Genus Choanomphalus Gerstfeldt, 1859 192 



Genus Poecilospira Morcli, 1853 194 



IX. Family Bulinidae 196 



Genus Indoplanorbis Annandale and Prashad, 1920 . . . 196 



X. Genera Wrongly Referred to Planorbidae 202 



Genus Nautilinus :\Iousson, 1872 202 



Genus Palaeorbis Beneden and Coemans, 1867 202 



XI. Bibliography 204 



