University of Michigan 



contortum 98, 16 



medianum HI, 7, 20, 41 



noveboracense. . . Ill, 18, 41 



pauperculum 



98, 16; 111, 7, 18,'41 



crystalense Ill, 7, 41 



nylanderi Ill, 41 



peraltum var Ill, 7, 41 



punctatum simplex. Ill, 7, 41 



roperi Ill, 15, 41 



var IIL 41 



sargenti Ill, 7, 41 



sp 98,16; 111, 22, 42 



splendidulum Ill, 7, 41 



tenuissimum 



98, 16; 111, 7, 41 



var labile 



98, 16; 111, 7, 20, 41 



brevium Ill, 7, 20, 42 



brevius 98, 16 



vesiculare. .98, 16; 111, 7, 42 



Plagiola 106, 22; 112, 42, 51 



donaciformis 112, 50 



elegans 112, 50 



lineolata 112, 42. 51 



opacata....l06, 17, 24, 26, 27 



n. subsp 106, 27 



sallei 106, 24, 27 



securis 112, 51 



Plagicrchis 93, 3, 4 



corti 93, 3 



notabilis 93, 4 



Planorbula armigera. . . .111, 34 



Planorbis 98, 3; 106, 36 



altissimus 98, 7, 11 



antrosus..l02, 4; 111. 32, 33 



portagensis Ill, 33 



striatus 



...98, 11; 111, 6, 15, 18: 33 



var 111. 22 



campanulatus. . . .111. 20, 34 



minor Ill, 34 



rudentis Ill, 34 



var Ill, 6 



circumstriatus.98, 11; 102, 4 



deflectus 111. 7, 20, 34 



var 98, 11 



exacuous 



..98, 11; 111, 7, 11, 15, 34 



megas 98, 11 



obliquus 98, 11 



parvus 



98, 5, 12; 111, 7, 15, 17, 18, 

 34 



var 98, 12 



walkeri 98, 12 



sp Ill, 22 



trlvolvis 



98, 12, 14; 102, 4; 111, 6, 

 15, 16, 32 



macrostomus 98, 12 



var 98, 12 



umbllicatelhis 



98, 12; 111. 7, 15, 34 



Platynaias 112, 33, 34, 35 



compressa 112, '33 



Plectomerus 112, 9 



crassidens 112, 9, 10 



trapezoides 112, 10 



Plethobasus cyphyus. . . .112, 19 



Pleurobema 112, 4, 20, 21, 68 



aesopus 112, 19 



amabile 112, 27 



appressa 112, 7 



catillus 112, 23 



clava 112, 21. 25, 26, 68 



coccineum pauperculum. 



112, 24 



conica 112, 20 



conradi 112, 20 



cor 112, 6, 7, 27 



cordatum.112, 6, 21, 23, 24, 25 



cuneata 112, 20, 25, 26 



sulcata 112, 68 



cyphia 112, 19 



dolabelloides 112, 19 



lewisi 112. 27 



maculatum 112, 20 



modicum 112, 27 



mytiloides 



112, 20, 21, 24. 25, 26 



obliquum catillus. 112. 23, 24 



cordatum 112, 23 



rubrum 112, 25 



plenum 112, 23 



