52 University of California Publications in Zoology [ Vou. 14 
the breadth of the area comprehended by the latter writer. (Unfor- 
tunately, we do not know the extent of the area designated by Thorade 
as ‘‘vor San Francisco’’). This would be in accordance with conditions 
known to occur elsewhere along the California coast, where the inshore 
waters are colder than those found at considerable distances from 
land. 
Jon ~ Feb, Mar. Apr. May dun. Jul Aug, Sep. Oct. Nov. Dec Jan 
Fig. I. Relations between local air and water temperatures. The con- 
tinuous line is based on the monthly means for the Pacific Ocean, near San 
Francisco, according to Thorade (1909). The dotted lines are based upon 
the monthly means for air temperature at San Francisco, one of these being 
plotted according to figures of Thorade, the other according to the records of 
United States Weather Bureau. 
In figure I, we have a curve representing the annual temperature 
eyele for the Pacific Ocean, ‘‘off San Francisco,’’ along with two 
curves representing the air temperature in that city. The curve 
” 
for ocean temperature and one of those for air temperature are 
based upon a diagram of Thorade’st® (1909), the other curve for air 
temperature being based upon the records of the San Francisco station 
of the United States Weather Bureau for the past forty years. 
The mean ocean temperature for the year, according to Thorade’s 
figures, is 12°86 C (55°13 F). For the air temperature of the city, 
MeAdie (1913) gives 12°96 C (54°96 EF) as the most reliable mean." 
The water eurve of Thorade exhibits two annual maxima, one 
in June, the other in October, and he seems disposed to believe that 
13 Thorade, 1909, p. 72. This writer’s figures for ocean temperature are based 
upon data collected by German steamers in the years 1898 to 1904, and pub- 
lished by the Deutsche Seewarte; also upon certain earlier records of the 
‘ Albatross’’. , 
14 The figures upon which Thorade’s curve for air temperature is based 
yield a mean of about 18°4 C, This writer cites another set of monthly means, 
attributed by him to Hann, the average of which is 12°9 C, while the figures of 
Hann himself (1906) give a mean of 13°2 C. We have thus a variety of figures 
to choose from. 
