138 TERRESTRIAL AIR-BREATHING MOLLUSKS. 



Morch, Am. Journ. Couch., IV. 27, PI. III. Figs. 1, 4(1868). — W. 0. Bixxf.y, 



L. & Fr.-W. Sh., I. 28 (1S69). 

 Helix, pcllucida, Fabricius, Fauna Gr., 389, excl. syn. Muller (1780). 

 Helix domestica, Strom. 1 Der Tronh. Vidensk., III. 435, PL VI. Fig. 15. 



Godhavn, Greenland, on ArcTiangelica officinalis. 



My figure is from a typical specimen in the British Museum. For other 

 figures and much information regarding the species, see Morch, 1. c. 



Animal bluish-gray, head black ; mantle edge bluish-gray, densely speckled 

 with black ; hinder part of foot pale gray. The lobe of the mantle very small, 

 by which latter character and the smaller number of whorls it is distinguished 

 from pellucida. (Muller in Morch, 1. c.) 



I have seen no specimen of the species. 



Vitrina Pfeifferi, Newcomb. 



Shell moderately depressed, smooth, shining, pellucid, greenish- white ; 

 whorls 3, the last composing most of the shell ; suture very finely mar- 

 gined ; aperture large, obliquely and roundedly ovate ; lip thin, 

 Fig. 53. columella arched. Diameter, 5 mill. ; axis, 2 mill. (Newcomb.) 



Iy^# : '\ Vitrina Pfeifferi, Newcomb, Proc. Cal. Acad. Nat. Sci., II. 92 



Y P f tifferi (1861). — Tryon, Am. Journ. Conch., II. 244, PL III. Fig. 



euiarged. ' 3 (1866). —W. G. Binney, L. & Fr.-W. Sh., I. 28, Fig. 26 



(1869). 



I have traced this species over all of California as far south as Fresno County ; 

 in Nevada, Colorado, at St. George, Utah, at Fort Wingate, New Mexico. It 

 may therefore be said to inhabit both the California Province and the Central 

 Region. It is, as usual in the genus, found at high elevations. 



Like V. limpida it is variable in color. 



Jaw as usual in the genus. 



The lingual membrane has over 50 — 1 — 50 teeth, with 10 perfect laterals. I 

 figure a central and lateral (PL II. Fig. A), and one extreme marginal. 



Vitrina exilis, Morelet. 



Shell subperforate, rather convex-depressed, very thin, pellucid, hyaline, 

 very lightly and distantly striate ; suture impressed, margined ; whorls 3, rap- 



1 This name I give to a little snail, which is represented by Fig. 15, since I find noth- 

 ing in Linne's Systema Nat. to which I can with certainty refer it. It is small, ovate- 

 rounded, and somewhat convex above, and shows 3 small and flat whorls on the one side. 

 The aperture is large and may be called almost entirely round, and the columella, or part 

 attached to the snail's house, comprises a small segment, or may be inscribed in an exact 

 circle. The shell is yellowish, and so brittle that one cannot pick it up without breaking 

 it in pieces. It contains a bluish snail. It is found in great numbers under the moss or 

 turf on houses, and is sometimes fully as large as the figure, which represents both the 

 upper and lower sides. (Strom.) 



