134 AMERICAN SPECIES OF VERTIGO. 



possibly be unknown intermediate links in the distribution 

 between Alaska and California. 



Perplexing forms are found in the occidentalis territory of 

 the upper San Bernardinos, where Mr. S. S. Berry has col- 

 lected many specimens, such as those listed by him as V. m. 

 parietalis (Nautilus xxx, 38). Figs. 8, 80, 8ft, on page 124 

 represent specimens having the subcylindric shape of 

 parietalis; there is a very small crest close behind the lip 

 (smaller than in parietalis, but larger than in typical occiden- 

 talis) . The teeth vary from quite as small as in the type of 

 occidentalis, or as in the most fully toothed forms of V. m. 

 castanea, to as large as in some parietalis; and in some ex- 

 amples which seem to be adult, there is no angular lamella. 

 The columellar lamella is usually deeply immersed. The base 

 is minutely perforate, or in some specimens scarcely so. 

 Length 2.5, diam. 1.35 mm., or slightly smaller. It seems to 

 be an intermediate stage between parietalis, castanea and 

 occidentalis, some individuals resembling one, others another 

 of these races. 



25/. VERTIGO OCCIDENTALIS Sterki. PL 10, fig. 11 ; page 124, 

 fig. 7. 



The sheU is perforate, and shortly rimate, globosely ovate, 

 the spire being convexly conic, summit obtuse ; decidedly wider 

 at the last whorl than at the penult ; of a dull hazel color, some- 

 what glossy, subopaque when adult, of 4y 2 rather convex 

 whorls, the last having a small external dent over the lower 

 palatal fold, but no ridge or crest behind the peristorne. The 

 aperture is rather large, obstructed by five teeth : parietal la- 

 mella short, a very small angular lamella near it ; columellar 

 lamella about equal to the parietal, rather deeply placed ; both 

 palatal folds short, the lower slightly larger. No palatal 

 callus. The outer lip is thin, narrowly expanded, projecting 

 forward above the middle ; columellar margin broadly dilated 

 and reflected. 



Length 2, diam. 1.25 mm. ; 4y 3 whorls (type, p. 124, fig. 7). 



Length 2.2, diam. 1.4 mm., aperture 0.95 mm. ; 4y 2 whorls 

 (topotype). 



