THE NAUTILUS. 57 



A colony of these snails, on leafy shrubs growing on sand 

 hills near the ocean, supplied the smallest individuals. Snails 

 on salicornia and other plants providing abundant shade fur- 

 nished perhaps the largest number of solid white shells. 



Midway between the ocean and the bay, on an exposed 

 plateau, I found the largest number of highly-colored shells, 

 many immature or just come to maturity, on leafless plants 

 like fouquiera, where the variegated color was an excellent 

 protection. It was very difficult to see these snails on the 

 bushes, even near at hand, except as projecting knobs on the 

 stems against a background of sky. 



The usually chalky-white shell seems to have a choeolate- 

 bro\^Ti epidermis, which varies in intensity at different stages 

 of its growth, often nearl}^ or quite absent, thus producing the 

 irregularly interrupted and very variable bands. This colored 

 stratum is thin and can be worn away with a knife-blade with- 

 out injury to the shell, and in age seems to naturally but 

 irregularly wear away, producing as many designs as there 

 are individuals. 



I have collected thousands of specimens called Helix levis 

 at San Quintin bay, at the Rosario mission some eighty miles 

 southward, and on the peninsula east of Cedros Island, which 

 seem to me to only differ from the Magdalena Island shells in 

 size. All these localities are arid ; rains occur at irregular 

 periods, sometimes three years or more apart, but copious fogs 

 from the sea nightly refresh the vegetation. 



Pilsbry speaks of the known areas of levis and areolata as 

 separated by a "long reach of coast whence no land snails 

 are knoAvn." From Turtle bay (a portion of, and not synon- 

 ymous with San Bartolome bay, as I am told) to Magdalena 

 bay is an arid coast unexplored by naturalists, from tlie lack 

 of water and landing places, mainly unknown because over- 

 land trails traverse this portion of the peninsula away from 

 the sea. But there is no reason to doubt the presence of this 

 snail in some form through the entire region from San Quintin 

 bay to Cape San Lucas. 



I presume that the older naturalists, like many modem 

 naturalists, collected sparingly, but selected specimens show- 



