VI THE NAUTILUS. 



Potamolithus microthauma n.sp 87 



Potamolithus Orbignyi, n.sp 88 



Potamolithus Rusbii Pils., n. sp 87 



Potamolithus Sykesii, n. sp 88, 89 



Pseudopartula Pfr. . . . , 109, 110 



Puget Sound, notes on some shells from 68 



Punctual conspectum var. pasadense Pilsbry, n. var. ... 21 



Pupa, a new form of 143 



Purpura lapillus var. umbricata 85 



Pyramidula strigosa, young 119 



Schmacker B. (obituary) 72 



Shells of Maryland 23 



Sinistral land shells 104 



Snailery, my 113 



Some laud shells of Michigan 84 



Spuaeria, a word about 29 



Sphyradium (Pupa) edentulum Drap., the systematic posi- 

 tion of 75 



Sulcobasis, anatomy of 119 



Syuapterpes, n.gen 46 



Trachydermon Sharpii Pilsbry, n.sp 50 



Tray of shells from Denmark 124 



Unionidre, descent and distribution of 5 



Unio Askewi Marsh, n.sp., pi. I, figs. 3,4 91, 121 



Unio Brimleyi Wright, n. sp 138 



Unio Burtchianus Wright, n. sp 137 



Unio Kirklandianus Wright, n. sp 136 



Unio Lehmanii Wright, n. sp 138 



Unios, the muscle scars of 29 



Unio Piukstouii Wright, n.sp 136 



Unio superioriensis Marsh, n.sp., pi. I, figs. 1, 2, 5 . . . .103, 121 



Unios of Illinois River 106 



United States Umonidaj, contribution to a knowledge of . 136 



Vallonia pulchella in Pittsburgh 143 



Van Nostraud, Henry D. (obituary) 93 



Vertigo coloradensis and its allies 134 



Vitrea cellaria Mull., notes on 142 



Weight and size of shells 



Zonites glaber Stud, and Zonites lucidus Drap. in green- 

 houses, Seattle, Washington 70 



