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CONTENTS 



Page 



Introduction 3 



Description of Species 4 



Genus Planorbis Miiller 



Section Paraplanorbis Hanna 



Planorbis (Paraplanorbis) condoni, n. ep. 

 Planorbis (Torquis) ecabiosus, n. sp. 



Genus Parapholyx Hanna, new name 

 Parapholyx paekardi, B. sp. 



Genus Carinifex Binney 

 Carinifex, sp. 



Genus Vortieifex Meek 



Vorticifex binneyi (Meek) 

 Vortieifex condoni, n. sp. 

 Vortieifex, sp. 



Genus Lanx Clessin 



Lanx moribundus, n. sp. 

 Lanx nuttallii (Haldeman) f 



Genus Paludestrina d'Orbigny 



Paludestrina microcoecus (Pilsbry) 



Genus Valvata Miiller 



Valvata oregonensis, n. sp. 



Genus Viviparus Montfort 

 Viviparus, sp. 



Genus Pisidium Pfeiffer 

 Pisidium, ep. 



List of Localities 13 



Explanation of Plates 15 



