2IO CAI.IFORNIA ACADEMY OF SCIENCES. 



25° 30', east coast). They differ from the usual forms 

 in a short, oval shape, no divergence of mouth, and small 

 size. The extreme of smallness is, length i.io, breadth 

 0.50 inch. Those from the Sierra Laguna are a little 

 larger, but intergrades occur up to the largest, which are 

 1.90 long and 0.70 wide. The average size of the species 

 may be given as 1.25 long and 0.60 wide, or more robust 

 than in Binney's figure. No clue to these variations is 

 derived from altitude on the mountains, ex'cept that those 

 found highest are of a darker brown color. Large 

 numbers were obtained living, when other species were 

 inactive in the month of May. 



B. PA1.1.IDIOR Sowerby, 1833. Mr. Eisen obtained 97 

 shells near San Jose del Cabo, and Mr. Bryant 12 near 

 Point Arena. They show all the forms between that fig- 

 ured by W. G. Binney as typical and Gould's D . vcgeiiis 

 (which was figured as a dark shell, but described as 

 white). In size they vary from 1.80 inch long and i 

 wide to 1.35x0.60. Mr. Eisen brought only one from 

 the Sierra fig region, of middle size, and considered it 

 almost entirely a lowland species. The specimen from 

 the fig region has vertical riblets on the three upper whorls, 

 and fewer of them are to be found on some of those from 

 lowlands. This one also has rather light revolving strice, 

 as in B. proteus, suggesting hybridit}-. It was often 

 found ascending trees. 



B. piLULA W. G. Binney, 1861. Mr. Bryant alone 

 obtained six specimens of this species, at Punta Arena, 

 which are larger than Binney's types, looking more like 

 a small variety of B. stifflatus, measuring 0.90 inch long, 

 0.60 wide. (Binney's figure is much smaller than the 

 size he gives.) It differs, however, from the young of 

 B. suff,atus, of same size, in having an open umbilicus. 

 One specimen has faint traces of two bands on the body. 



