164 



hymnxa truncatula6o, 61, 62, 64, /;, 73 



tryoni 74 



tryoniana 74 



vahlii 7^, 75 



wormskioldi (75) 



zrmanjae 61, 65 

 Lymnsidae jj> 

 Lymnieus (60) 



columellus {70) 



emarginatus (68) 

 Lymnea (60) 



cornea (77) 

 Lymneus (60) 



caperatus (79) 



desidiosus (73) 



emarginatus (68) 



galbanus (73) 



humilis (73) 



megasomus (67) 



minutus (72) 



reflexus (77) 

 Lvmnophjsa (61) 

 Ljmnula (60) 

 Ljmnus (60) 

 Lyogyrus /jS 



granum 1/8, 1 19 



lehnerti (117) 



Macrocyclis 33 



vancouverensis (34) 

 Macrophysa (lOo), /oi 

 Margarita oregonensis (128) 

 Margaritana 131 



falcata /J2 



margaritifera II, IJi 

 Melania 117 



canaliculata (116) 



conica (116) 



plicifera (116) 



silicula (116) 

 Melantho decisa (125) 

 Menetus (81), .?^, 86 



exacuous 91 



opercularis 92 

 Microphysa 99 



laneingi 44 



pygmaa (53) 



Stearns ii (44) 

 Mouretia (ill) 



Muretia (iii) 

 Musculium jayanum 139 



lenticula 140 



partumeium 139 



raymondi 138 



tenue 139 



transversum 139 



truncatum 140 

 Mya complanata (133) 



margaritifera (132) 



radiata (126) 

 Myxas (104) 



Naiades i2j 

 Nauta (104) 



hypnorum (106), (107) 



polaris (107) 

 Nautilina (83) 

 Nautilus crista (96) 



lacustris 97 

 Neritostoma j'j, (61) 



Odostomia (115) 

 Oligolimax (36) 

 Omplialia (61) 

 Omplialolimnus (61), 63 

 Omphiiscola 60, (61), 62 

 Onchidella //2 



borealis //2, 113, 114 



carpenter! 113 



celtica 112, 113, 114 



fioridana 114 

 Onchidiida; lis 

 Oncliidium //2, 114, 115 



boreale (112) 



celticum 113 



nigricans 112 



schrammi 114 



typlis 112 

 Orbis (81) 

 Oreohelix 5/ 



cooperi 52 



Etantoni 52 



strigosa 5/, 52 

 Oxyloma55 



hungarica 55 



Parana (36) 



Paludina cincinnatiensis 118 



