162 CALIFORNIA ACADEMY OF SCIENCES [Proc. 47H Ser. 
graphic distribution in the supposed dichromatism. Such dis- 
tribution is well illustrated in Puffinus chlororhynchus. Ac- 
cording to the tables of measurements, the dimensions average 
greater in the Los Coronados than in the San Benito specimens. 
Dr. Godman has established the identity of “O. socorroensis” 
with Oceanodroma monorhis (Swinhoe).* It is significant 
that O. leucorhoa and “O. monorhis” are reported for the 
Asiatic coast. 
In short, the material under consideration evidences that “O. 
beali’”’ is based upon geographic variation in size (the dimen- 
sions averaging less than in Atlantic specimens), “O. beldingi’” 
upon individual variation, “O. kaedingi”’ upon geographic 
variation in size (the dimensions averaging less than in speci- 
mens from Middle California, Oregon, and Alaska), and “O. 
socorroensis’ upon dichromatism. However, before a final 
conclusion is reached concerning “O. kaedingt’”’ and “O. socor- 
roensis’ (=“monorhis”), an extensive series of specimens of 
these supposed species, in new plumage and with nasal tubes 
undistorted, must be collected and compared with fresh north- 
ern specimens. In the meantime I have included the two names, 
with a question, in the synonymy of O. leucorhoa, leaving to 
the future the attempt to rescue them from limbo. 
The usual point-of-wing-formulas, throughout the entire 
series, are: primary 2>3>1>4 and 2>3>4>1, the former pre-- 
dominating. The extreme base of the lateral rectrices is white 
in most of the specimens before me having white upper tail- 
coverts. Certain specimens display as much white on the lower 
tail-coverts as do some examples of O. castro. No. 473 C. A. 
S., white upper tail-coverts, November 15, has a light patch on. 
the lining of the wings, resembling that in O. homochroa. Nos. 
468 and 472 C. A. S. (both with white upper tail-coverts) have 
indications of such a patch. In No. 472 the dark tips of the 
white upper tail-coverts are as broad as in several O. castro, 
but are dark gray instead of black. The line of demarcation 
between the gray and white is not oblique in all specimens. The: 
wing-bar generally penetrates further into the lesser coverts 
than it does in O. castro. Furthermore, in that species the dark 
central upper tail-coverts, usually present in O. leucorhoa, ap- 
1 Mon. Petrels, p. 33. 
