VI 



THE NAUTILUS. 



Somatogyrus amnicoloides Walker, n. sp. (Fig. 3) 



Somatogyrus, apical characters in . 



Somatogyrus crassilabris Walker, n. sp. (Fig. 4) 



Somatogyrus wheeleri Walker, n. sp. (Figs. 1, 2) 



Sonorella lioderma Pils. (PI. II, f. 7) 



Sonorella lohrii Gabb (PI. II, f. 8) . 



Sonorella merrilli Bartsch 



Sonorella peninsularis Pils. (PI. II, f. 4) 



Sonorella ultima Pils. (PI. II, f. 5) 



South Dakota, Mollusca of 



Stain for Radulse .... 



Tethys (Neaphysia) californica (Cooper) 



Unio cor Conrad, observations on 



Unio crapulus Lea .... 



Unio lewisii Lea .... 



Unio viridis Raf. .... 



Unionidae, some exceptional cases of breeding among 



Urocoptis cyclostoma anafensis Henderson 



Uruguay, two new bivalve shells from 



Vallonia costata montana Sterki 



Venezuela shells ..... 



Vitrea carolinensis Ckll .... 



Vitrea cryptomphala Clapp, n. sp. (Fig. 1) 



Vitrea indentata Say .... 



Viviparus malleatus Reeve in Massachusetts 



