80 GASTROCOPTA, NORTH AMERICA, WEST INDIES. 



being found almost anywhere snails live in Texas, New Mex- 

 ico and Arizona, between the 97th and 113th meridians, ex- 

 cept in the higher mountains. About 150 lots are in the col- 

 lection of the Academy. 



Specimens from a dry cliff in the very arid Big Hachet 

 Mts., N. M., near the Mexican boundary, are all small, length 

 1.8, diam. 0.72 mm., very pale buff, and without a crest be- 

 hind the lip. 



The examples from Guajadami, Lower California, are par- 

 affine-whitish, rather long and narrow, fig. 4 measuring, length 

 2, diam. 0.72 mm. The crest behind the lip is very low but 

 perceptible. This locality is widely separated from the rest 

 of the known occurrence of hordeacella. 



Mr. Vanatta has published a series of figures, drawn to the 

 same scale with the camera-lucida, to illustrate the very great 

 variation in size and shape in this subspecies. His plate is 

 reproduced in plate 16, the specimens illustrated being from 

 the following localities : 



Figs. 1, 3, 5-8, 12, 13, 15, 16, 20-22, Key West, Florida. 

 No. 104029. 



Figs. 9, 10, 14, 17-19, 25, Bahia Honda Key, Fla. No. 

 105521. 



Figs. 4, 24, 26, 27, Summerland Key, Fla. No. 102742. 



Figs. 2, 11, 23, New Braunfels, Texas. No. 68888. 



Each lot contains specimens from a single station of only a 

 few feet extent, except the New Braunfels lot, which was 

 from stream debris. By its great variability and often larger 

 size, hordeacella contrasts with pellucida. 



22d. G. pellucida parvidens Sterki. PL 17, fig. 8. 



' ' Quite small ; apex more acute than in typical examples [of 

 hordeacella] and outline more obovoid; peristome rather 

 abruptly but narrowly everted; lamellae and folds small, 

 especially so the upper palatal, often being a mere trace; 

 basal absent or very small; color pale horn. Alt. 1.5 to 2 

 mm." (Sterki). 



Size and shape are variable in this race, which differs from 

 hordeacella by the smaller lamellae and plicae, the angular 



