13 



XXII. LIMNEUS. MUD-SHELL. 



So named from their general location in ponds, ditches, 

 and other stagnant receptacles. 



100. Limneus auricularius. Wide-mouth Mud-shell. 



101. Limneus pereger. Puddle Mud-shell. 



102. Limneus Scaturiginum. BrooTc Mud-shell. 



103. Limneus glutinosus. Glutinous Mud-shell. 



104. Limneus stagnalis. LaJce Mtid-shell. 



105. Limneus fragilis. Brittle Mud-shell. 



106. Limneus elongatus. Eight-whirled Mud-shell. 



107. Limneus palustris. Marsh Mud-shell. 



108. Limneus fossarius. Ditch Mud-shell. 



109. Limneus detritus. Worn Mud-shell. 



XXIII. PHYSA. BUBBLE-SHELL. 



So called from the thin and inflated appearance. 



110. Physa fontinalis. Stream Buhhle-shell. 



111. Physa alba. WJiite Bubble-shell. 



112. Physa rivalis. River Bubble-shell. 



113. Physa Hypnorum. Slender Bubble-shell. 



