114 CALIFORNIA ACADEMY OF SCIENCES [Proc. 47m Ser. 
Upper Mandible Mada 
Sex | Wing | Tail | Culmen Tarsus |Toe and 
Depth | Width Claw 
Maximum........... o | 351 | 127 | 46.1 | 13.7 | 19.4 | 53.9 | 72.9 
Minimum........... o | 320 | 103 |; 40 11 16.2 | 47.4 | 64 
IWiGai mips lo auetee ees o | 333 | 114 | 43.4 | 12.2 | 17.9 | 50.2 | 67.8 
Maximum........... Q@ | 344 | 123 | 43.9 | 12 18.5 | 52.2 | 70.5 
Minimum........... @ | 318 | 110 | 39.9 | 11 16.5 | 47.1 | 63.2 
NW IGEN OUaa eles Shea sue a) © | 330 | 116 | 41.9 | 11.5 | 17.4 | 49.8 | 66.6 
From the above, it appears that sexual variation in size plays 
an unimportant part in this species. 
Puffinus opisthomelas Cowes: BLACK-VENTED SHEARWATER 
Plates 14-16 
Coves—Pufiinus opisthomelas, II, 139, 144. 
SaLtvin—Pufinus opisthomelas, 369, 380. 
GopMan—Pufiinus opisthomelas, xli, 109, pl. 30. 
Examination of the type of Puffinus opisthomelas Coues 
(No. 16991 U. S. Nat. Mus.) and the type of Puffinus auricu- 
laris C. H. Townsend (No. 117540 U. S. Nat. Mus.) shows 
that each of these types represents a distinct species and that the 
small white-breasted shearwater occurring commonly off Cali- 
fornia is Puffinus opisthomelas Coues, of which Puffinus couesi 
Mathews’ is a synonym.’ 
After breeding on Lower California islands, Black-vented 
Shearwaters migrate northward along the coast as far at least 
as Vancouver Island, their fly-line thus extending about fifteen 
hundred nautical miles. 
In the vicinage of Point Pinos, California, neither Mr. Beck 
nor myself has met with these shearwaters in May and June. 
Stray individuals occasionally appear at the end of July, but 
ordinarily the first arrivals come in August and sometimes not 
before September. They are irregularly abundant through 
autumn and more or less common thereafter until the close of 
April. I found them common through December, 1912, but 
they were extremely wary and I only succeeded in securing 
fifteen specimens, several of which exhibited great functional 
1Cf. Birds Austr., v. 2, 
?In the Auk for @ccober: 1917, pp. 472, 473, Mr. Oberholser has also reached this 
conclusion, 
