1918] Swarth: The Pacific Coast Jays of the Genus Aphelocoma 421 
these two skins are typical of californica is an argument in favor of 
the specific distinction of the two forms. 
As regards the first of these two points, it will be noted that 
although series of californica from northern California (A. c. im- 
manis), are closely similar to hypoleuca, the form geographically 
closest adjacent to the range of hypoleuca ( A. c. californica, of the 
San Pedro Martir Mountains) is the farthest removed from it in all 
its characters. 
As can be seen on the accompanying table (opp. p. 408) the course 
of variation in Aphelocoma californica is, in general terms, as follows. 
At the northern extreme of its range there is a large, pale colored 
form, restricted to the interior valleys and mountains. This, in the 
central coast region merges into a large, dark colored race, which, 
in turn, to the southward passes into the smaller, but dark colored, 
race that extends into northern Lower California. Then, abruptly, 
after what appears to be an absolute break in continuity of range, 
there is the large, pale colored form, hypoleuca. 
The fact that hypoleuca has been heretofore described as smaller 
than californica is probably due to comparisons being made with 
series of the form ammanis. Compared with A. c. californica from the 
Santa Cruz or San Diegan districts it is, as shown in the accompany- 
ing table, of larger size than these birds. Measurements of hypoleuca 
are about equal to those of immanis from the Sacramento Vallev or 
Sierra Nevada, and smaller than those of series from extreme northern 
California and Oregon. 
Transmitted June 12, 1917. 
