34 University of California Publications in Zoology [Vol. 18 



salinity of the water of the bay was greatest during the fall months 

 and least during the spring months. This is shown in the appended 

 table of salinity measurements for three stations chosen at the head 

 of the day and not far from the places where the Teredo had caused 

 damage. 



These stations may be described as follows (Sumner, et al., 1914, 

 p. 153, pi. 4) : 



Station 4975. Tang. Crockett Whf., S 74° E; Carquinez St., N 50° W; 

 Tang. Selby Whf., S 69° W. Well within the entrance to Carquinez Strait, near 

 Crockett; depth 14%-12 fms. 



Station 4976. Tang. Crockett Whf., S 76° E; Carquinez St., S 48° E; Mare 

 Isl. St., N 27° E. In the middle of the ship channel, directly south of the south- 

 eastern end of Mare Island, and near the long dike; about 1 mile W by N from 

 Station 4975; depth 101/2-9% fms. 



Station 4977. Carquinez St., N 71° E; Lone Tree Pt. Whf., S 36° E; Pinole 

 Pt. Tang., S 53%° E. In the middle of the ship channel and about l^/^ miles 

 W by S from Station 4976; depth 5%-5 fms. 



In the following tables, compiled both for salinity and temperature 

 from the published results of the biological survey of San Francisco 

 Bay, "the 'surface' figure is the mean of the surface figure recorded 

 during the flood-tide observation and that recorded during the ebb- 

 tide observation. Similarly, the 'bottom' figure is the mean of the 

 ebb and flood figures for the bottom" (Sumner, et al., 1914, p. 28). 



SALINITY AT STATIONS IN UPPEE SAN PABLO BAY 

 Parts Per Thousand 



Av. for entire year, 13.21 17.27 4.06 14.23 17.16 2.93 15.46 19.25 3.79 



From this table for salinity it appears that of the six periods of 

 observation the greatest salinities at all three stations were observed 

 both at the surface and at the bottom during the period October 7-12, 

 1912. This period corresponds in general with the period of least 

 discharge of fresh water from the Sacramento and San Joaquin river 

 system, and lags only a little behind the month (September) in which 

 the average minimum monthly discharge is found to occur. 



