THE NAUTILUS. V 



Naiad Fauna of the Mississippi River, notes on the 80 



Navajo Nation 1 



North Dakota, shells from Jamestown 29 



Olivella biplicata Sowb 117 



Olivella boetica, new varieties 118, 119 



Oreohelix depressa 6, 12 



Oreohelix clutei Ferriss, n. subsp 5, 13 



Oreohelix cumrningsi Ferriss, n. subsp 5, 12 



Oreohelix neomexicana Pils 5 



Oxystyla floridensis Pils 108 



Pachycheilus indiorum (Morelet) 44 



Pachycheilus lacustris (Morelet) 37 



Pachycheilus pottsianus Hinkley, n. sp 54 



Pegias fabula Lea 88 



Paravitrea multidentata (Binn.) 28 



Pecten magellanicus Grnel 60 



Pecten (Patinopecten) rhytidus Ball, n. sp 77 



Pecten ( Plagioctenium ) hallae Ball, n. sp 76 



Pecten landi Cooke, n. n 137 



Pecten vaun Cooke, n. n 137 



Pennsylvania, land shells from Beaver Co 28 



Physa humerosa interioris Ferriss, n. subsp 2, 4 



Planorbis similaris Baker 68 



Planorbis trivolvis Say 10 



Plebecula Lowe 133 



Pleurobema oviforme Conrad 85 



Polita indentata umbilicata Ckll 14 



Polygyra auriculata Say 31 



Polygyra dentata Ferriss 28 



Polygyra multilineata altonensis Baker, n. var 65 



Polygyra profunda pleistocenica Baker, n. var 66 



Portland catalogue, species named in the 97, 124 



Praticolella bakeri Van 31 



Psammacoma brasiliana Ball, n. sp 132 



Ptychobranchus subtentum Say 88 



Publications received 31, 70, 104 



Pupilla hebes mut. albescens Ferriss 8, 14 



Pupilla syngenes Pils 



Pupoides marginata Say 14 



Pyramidula cumberlandiana Lea (pi. 1, fig. 1) 24 



Pyramidula cumberlandiana alabaina Clapp, n. var. (pi. 



1, fig. 3) 25 



Pyramidula cumberlandiana columba Clapp, n. var. (pi. 



1, fig. 5) 25 



Pyramidula from Alabama, a new species of 23 



Pyramidula picta Clapp, n. sp. (pi. 1, fig. 4) 23 



