xvi The Molluscan Family Planorbidae 



PART II 



The Planorbidae Inhabiting North and South America 



AND THE West Indies 



XII. Foreword 215 



XIII. Descriptions of New Species and New Varieties. . 218 



Genus Troyicorhis 218 



Tropicorbis shimeki, New Species 218 



Genus Helisoma 219 



Helisoma nnceps anticostianum, New Variety 219 



Helisoma anceps bartschi, New Variety 219 



Helisoma anceps idahoense, New Variety 220 



Helisoma anceps politum, New Variety 221 



Helisofna binneyi randolphi, New Variety 221 



Helisoma caribaeum cubense, New Variety 222 



Helisoma columbiense, New Species 222 



Helisoma kennicotti, New Species 223 



Helisoma pilsbryi preblei, New Variety 224 



Helisoma subcrenatum perdisjunctum, New Variety . . . 224 



Helisoma trivolvis marshalli, New Variety 225 



Helisoma campanulatum dalli, New Variety 226 



Helisoma campanulatum pleistocenicum, New Variety . . 226 



Helisoma campanulatum rideauense, New Variety . . . 227 



Genus Parapholyx 227 



Parapholyx effusa dalli, New Variety 227 



Parapholyx klamathensis sinitsini, New Variety .... 228 



Parapholyx pusilla, New Species 229 



Genus Planorbida 229 



Planorbula smithii, New Species 229 



Genus Menetus 230 



Menetus color adoensis, New Species 230 



Menetus cooperi crassilabris, New Variety 230 



Menetus cooperi planospirus, New Variety 231 



Menetus dalli, New Species 231 



Menetus dilatatus floridensis. New Variety 232 



Menetus labiatus, New Species 232 



Menetus portlandensis, New Species 233 



Illustrations of the Anatomy and of Shells 235 



Index to Text 521 



Index to Illustrations 527 



