498 CALIFORNIA ACADEMY OF SCIENCES. 



San Benito County, 



Of this county only about 65 square miles are shown, in 

 the triangle northeast of Monterey County and south of 

 Pajaro River. Only one addition to the list is known from 

 there, No. 45, found at "Soap Lake," a marshy expansion 

 of Pajaro River, named from the great alkalinity of the 

 water. This mineralization of the streams, together with 

 the increased dryness of the county^ cut off from much of 

 the sea breeze by the high Gavilan range of mountains sep- 

 arating it from Monterey County, shows why the only Heli- 

 coid species known from it is No. 32, though a few others 

 may exist, as well as some of the smaller forms, Limacoids, 

 etc. 



Monterey County. 



This extends from Pajaro River south for over 60 miles, 

 and the little known of the species found south of the part 

 on the map has been already given. The influence of the 

 moisture from the ocean on this part is shown by the 

 abundance of several species, between Monterey and 

 Carmel Bays, even on the apparently unsuitable granitic 

 soil, which is however partly covered with tertiary cal- 

 careous sandstone, wooded with pine, cypress and oak. 

 There and elsewhere near by, are found Nos. 1, 5, 6, 11, 19, 

 21. 24, 25, 31, 34, 38, 41, and 42, all within 10 miles of the 

 sea shore, and none are known from higher or more inland 

 localities except No. 37, as stated on page 363. By 

 comparing this with previous lists it appears that while 

 about the same number of species occur as in Santa Clara 

 County, about half of them are distinct, but mostly represen- 

 tative forms, and added together they make only 29 found 

 south of San Francisco Bay, while there were 36 east of there 

 (one of each list doubtful). Increased heat and dryness are 

 the chief causes of this decrease in species. 



