VERTIGO. 69 



The subfamily, in its present limits, is a new group. The 

 family Vertiginidae of Stimpson (Shells of New England, 

 1851, p. 53) comprised only the genus Vertigo including 

 V. simplex Gld., but Stimpson also characterized his family 

 by the want of inferior tentacles. 



From the literature it may be gathered that some Pupillidae 

 certainly belonging to other subfamilies are deficient in ten- 

 tacles, and according to Gredler, a reliable observer, V. genesii 

 has inferior tentacles. Further careful observations on many 

 species are needed. The inferior tentacles are usually very 

 short in Pupillidae, and may therefore be overlooked easily. 



A general likeness may be traced between the shells of the 

 genera now referred to Vertigininae ; it appears to be a na- 

 tural group ; though the variation is so great throughout the 

 family that definitions sufficiently elastic to cover any of the 

 groups larger than genera become too comprehensive to be 

 diagnostic. 



The genera fall into two main geographic divisions: 1. 

 northern or mainly Holarctic, including Vertigo, Trunca- 

 teltina, Sterkia and their satellite groups, and 2. Polynesian 

 and Tropical, with Nesopupa and the associated groups. 

 Places where these divisions overlap are extremely few. 



A list of fossil genera and species of Vertigininae follows 

 the account of the genus Vertigo. 



Genus VERTIGO Miiller. 



Vertigo 0. F. MULLER, Vermium terrestrium et fluviatilium 

 Hist., ii, 1774, p. 124, monotype V. pusilla Mull. 



Isthmia GRAY, London Medical Repository, xv, 1821, p. 239, 

 for ''Helix Isthmia, cylindrica Drap, t. 3, f. 30, 31," 

 pygmaa Drap. Cf. BALL. Tr. Wagner Inst. iii, pt. 2, p. 248 ; 

 Nautilus xvii, 1904, p. 114, and NEWTON and HARRIS, Proc. 

 Malac. Soc. London i, p. 72, footnote 1. GRAY, P. Z. S. 1847, 

 p. 176, type Vert, nitida = edentula Drap. 



Alcca, JEFFREYS, Trans. Linn. Soc. London xvi, 1830, p. 357. 

 -GRAY, P. Z. S. 1847, p. 176, type A. palustris Jeffr. = 

 V. antivertigo. PILSBRY, Nautilus xviii, 1905, p. 119. 



