THE NAUTILUS. Vll 



Somatogyrus decipiens Walker, n. sp. (PI. VI, figs. 10, 11). 86 

 Somatogyrus hendersoni Walker, n. sp. (PL VI, fig. 2) . 87 

 Somatogyrus hinkleyi Walker, n. sp. (PL VI, figs. 8, 9) . 87 

 Somatogyrus pygmseus Walker, n. sp. (PL VI, fig. 3) . 88 



Sphaerium pilsbryanum Sterki, n. sp. . ... . . 141 



Strange shells . . . . ... . . . 110 



Strobilops, Notes on the genus 78 



Strobilops quadrasi and S. trochospira . . . .79 



Stylommatophora, Some notes on the locomotive disk of . 49 

 Tagolanda, Land shells of . . . . . . .46 



Terebratula (Liothyris) sakhalinensis Ball., n. sp. . . 28 

 Texas, List of the shells from Amarillo .... 9 



Texas, Mollusca of McLennan County . . . .63 



Torinia discoidea sterkii Pils. & Van., n. subsp. (fig. 2) . 57 

 Trishoplita cretacea pergranosa Pils. & Hir., n. subsp. . 43 

 Trivia galapagensis, Notes on . . . . .11 



Trivia mangeriae, Note on . . . . . . .10 



Turbonilla (Chemnitzia) gabbiana . . . . .39 



Turbonilla (Chemnitzia) thaanumi Pils. & Van., n. subsp, 



(fig. 3) . . 58 



Unionidae, Supplementary notes on the breeding seasons 



of the Ill 



Unionidse in Pennsylvania, The breeding season of 91, 99 



Unioninse and Hyriinae, Remarks on the sub-families . 106 



Valvata humeralis californica Pils., n. subsp. . . .82 



Verrill collection ........ 33 



Verticordia (Haliris) granuloides Aldr., n. sp. (PI. V, fig. 10). 75 

 Vertigo nylanderi Sterki, n. sp. . . . . . . 107 



Vesicomya ticaonica Ball., n. sp. . . . . .63 



Vivipara lecythoides Bens, in California . . . .33 



Waldheimia raphealis var. albida . . . . .30 



Yates, Br. Lorenzo G. (obituary) 124 



