48 University of California Publications in Zoology [ Vou. 14 
H-5330 (== H-4981), at the lower end of San Pablo Bay, in the main 
channel. If we confine the temperatures for the latter station to the 
actual hours covered by the shoal-water observations, this figure be- 
comes 16°07 C. 
In the southern part of the bay a similar line of three stations, 
across the shoal area, east of the main channel, at a mean depth of 
two fathoms, gave a mean iemperature of 20°56 C In comparison 
“with this we have 18°48 C, which was the mean figure on the same day 
(July 23) for three ‘‘ Albatross’’ stations in the deeper waters of this 
section. 
Thus the figures for the summer temperatures of the upper and 
lower regions of the bay, as expressed in the preceding tables, are 
doubtless somewhat too low, since they are based exclusively upon the 
conditions in the deeper, somewhat cooler waters to which the regular 
hydrographic stations were confined. Conversely, it is probable that 
the winter temperatures of these deeper waters were somewhat higher 
than those of the great expanses of shoal water. 
It seems worth while to introduce here, during the passage of this 
paper through the press, the results of some temperature determina- 
tions made on March 5 and 6, 1914. Nine stations were chosen, cor- 
responding to certain of the primary hydrographic stations in each 
of the regions of the bay. Since two of these stations were visited 
twice, and since surface and bottom readings were obtained in all 
cases, the total number of figures is 22. The mean temperature thus 
obtained was 12°39 C. That found at the same stations and same 
phases of the tide, from February 13 to 27, 1912, was 112995 C. The 
agreement is certainly close. The higher figure for 1914 is perhaps 
to be accounted for by the fact that the observations for this year 
were made about two weeks later. 
Through the courtesy of the Morgan Oyster Company, we are able 
to present temperature records taken throughout six months of the 
year 1913 at their Millbrae and Dumbarton beds. The former bed 
is located between Point San Bruno and Point San Mateo, the latter 
being near the extreme southern end of the bay. The figures are pre- 
sented in Table 11. The temperatures given for April, May, and June 
are each based upon four readings, made twice per month at both high 
and low water. The other figures are based upon two readings only, 
both on the same day. The temperatures given are for the surface. 
These thermometer readings, we learn, were not made while the 
bulb of the instrument was immersed, but after the removal of the 
