434 ILLUSTRATIONS. 



51. Jaw of Euconulus 481 



52. Dentition of Euconulus 481 



53. Euconulus fulvus 482 



54. Euconulus chersinus polygyratus 482 



55. Jaw of Zonitoides arborea 483 



56. Dentition of Zonitoides arborea 483 



57. Zonitoides nitida 483 



58. Zonitoides arborea 484 



59. Zonitoides limatula 484 



60. Zonitoides minuscula 485 



61. Zonitoides exigua 485 



62. Sculpture of Zonitoides exigua 486 



63. Zonitoides milium 486 



64. Animal of Gastrodonta ligera 486 



65. Tail of Gastrodonta suppressa 486 



66. Jaw of Gastrodonta ligera . 486 



67. Dentition of Gastrodonta intertexta 487 



68. Gastrodonta intertexta 487 



69. Gastrodonta demissa 487 



70. Gastrodonta ligera 488 



71. Gastrodonta suppressa •. 488 



72. Jaw of Agriolimax agrestis 488 



73. Dentition of Agriolimax agrestis 489 



74. Agriolimax agrestis 489 



75. Agriolimax campestris 489 



76. Animal of Pyramidula solitaria 490 



77. Jaw of Pyramidula alternata 490 



78. Dentition of Pyramidula alternata 491 



79. Pyramidula alternata 491 



80. Pyramidula solitaria 492 



81. Pyramidula solitaria albina 492 



82. Pyramidula perspectiva 493 



83. Pyramidula cronkhitei anthonyi 493 



84. Pyramidula asteriscus 494 



85. Animal of Helicodiscus parallelus 494 



86. Jaw of Helicodiscus parallelus 494 



87. Dentition of Helicodiscus parallelus 494 



88. Helicodiscus parallelus 495 



89. Jaw of Punctum pygmaium 495 



90. Dentition of Punctum pygmgeum 495 



91. Punctum pygmseum 496 



92. Dentition of Sphyradium edentulum 496 



93. Sphyradium edentulum 496 



94. Jaw of Philomycus carolinensis 497 



95. Dentition of Philomycus carolinensis 497 



96. Philomycus carolinensis 497 



97. Jaw of Pallifera dorsalis 498 



98. Jaw of Pallifera hemphilli 498 



99. Dentition of Pallifera dorsalis 498 



100. Pallifera dorsalis 498 



101. Pallifera hemphilli 499 



102. Animal of Succinea 499 



103. Jaw of Succinea retusa 500 



104. Jaw of Succinea ovalis 500 



105. Jaw of Succinea avara 500 



106. Dentition of Succinea retusa 500 



107. Succinea retusa 500 



108. Succinea calumetensis 500 



109. Succinea retusa 500 



110. Succinea retusa magister 501 



111. Succinea retusa decampii 501 



112. S\iccinea retusa peoriensis ; 501 



113. Succinea ovalis 502 



114. Succinea avara 503^ 



115. Apertural folds of Pupillidse 504 



