The Nautilus. 



Vol. XXIII. NOVEMBER, 1909. No. 6 



THE KNOWN MOLLUSCA OF SAN BERNARDINO COUNTY, CALIFORNIA. 



BY S. S. BEKKY. 



In li,2;ht of the fact that accurate data bearing on the geographical 

 distribution of Californian land and fresh-water mollusca are still few 

 and far l)etween, it seems best to publish such items as may be 

 accumulated from time to time, and in this connection the following 

 notes (the result of several years desultory observation) may be of 

 interest. 



The district under present consideration comprises one of the 

 largest, if not the largest, counties in the United States, being more 

 than equal in area to any one of a number of our smaller States. By 

 far the greater portion of its area is swallowed up by the vast Mojave 

 and Colorado Deserts, and even at this late date is still almost an 

 absolute terra incognita so far as the mollusca are concerned. Of 

 necessity, therefore, the present paper treats almost exclusively of 

 the extreme southwestern corner of the county alone, namely, the 

 so-called San Bernardino Valley, with the adjacent San Gabriel and 

 San Bernardino Ranges of mountains which confine it on the north 

 and shut it off from the desert and the remainder of the county. 

 Even for this circumscribed distric^t, the present list makes no pre- 

 tensions to completeness, but is offered merely as a resume of our 

 present knowledge, with the hope that it may lead to further investi- 

 gation. Doubtless more than one interesting form still awaits its 

 discovery by some diligent collector, especially in the mountain reg- 

 ions (see Nautilus XXI, p. 121, and below). 



It is interesting to note that the above-mentioned valley is practi- 



