36 CALIFORNIA ACADEMY OF SCIENCES [Proc. 4TH Ser. 
No. Sex Species No. of Rectrices 
GAR Se 
1288 fof Diomedea nigripes.............-- Fourteen 
1237 fe) Diomedea trrorata............... Thirteen 
1003 of Pterodroma ph@opygia........... Thirteen 
1004 of 2 DOE Mie a Oars a ae SO Fourteen 
1138 ot Pierodroma inexpectata........... Thirteen 
9308 of Puffinus creatopus............... Thirteen 
854 of Pui nus COSCUTUSS ren ele Fourteen 
9577 fof BUT ENUS\OTASCUS Gaeta eee Thirteen 
9743 fos Puffinus tenutrostris............-. Fourteen 
Univ. Calif. 
18682 foe Puffinus bullert................. Fourteen 
18685 of 5 HEAL EMU AN Me NGAP AAP ae Oe Thirteen 
DICHROMATISM 
Dual coloration is a dominant condition in many Tubinares. 
In the nestling of the Galapagos Albatross (see plates 9, 10, 11 
and description in part VI), in the Giant Fulmar, Fulmar, 
Short-footed Petrel, Neglected Petrel, and Wedge-tailed 
Shearwater the bicoloration has been proven to be dichro- 
matic. In the following species, dwelt upon at length in parts 
V and VI, the character of the variation remains to be fully 
determined: Wandering Albatross, Sooty Albatross, Cape 
Petrel, Dark-rumped Petrel, Downy Petrel, Cooper’s Shear- 
water, Manx Shearwater, Black-vented Shearwater, Forster’s 
Shearwater, Dusky Shearwater, Sooty Shearwater, Slender- 
billed Shearwater, Leach’s Petrel (including “Kaeding’s” and 
“Socorro” petrels), White-bellied Petrel, and Diving Petrel. 
The status of the Caribbean Petrel is also in question. 
Long ago it was pointed out by Dr. Stejneger* that there 
exists a difference in the geographic range of the light and 
dark phases of the Fulmar during the breeding season. ‘There 
is also a geographic distribution in the phases of the Wedge- 
tailed Shearwater. In the Hawaiian Archipelago the light 
phase prevails almost exclusively, but on San Benedicto Island, 
Revilla Gigedo Group, only a minority are of the light phase. 
The light phase of the Red-footed Booby, on the contrary, is 
the dominant form in the Revilla Gigedo Group, and on the 
Galapagos Islands the dark phase is in the ascendency. Fur- 
1 Bull. U. S. Nat. Mus. No. 29, 1885, p. 93. 
