144 CALIFORNIA ACADEMY OF SCIENCES [Proc. 47H Ser. 
suddenly dropped and scurried into its burrow, raising a cloud 
of dust. 
May 23. It is too early yet for eggs. 
A series from San Benedicto Island illustrating the transi- 
tion from the natal down to the definitive feathers would be 
especially instructive, showing whether or not the light phase 
is light-colored from birth, and the dark phase, dark-colored. 
It is apropos to note that Mr. William Alanson Bryan states 
that a nestling of the light Marcus Island bird is “a smoky 
lilac-gray over the back and top of the head, and very light 
pearl gray on the under parts, darkest on the abdomen,’ and 
that Mr. T. Iredale notes that the “down of the young was 
dark grey’”® in the dark phase prevailing on the Kermadec 
Islands. 
The Expedition specimens show some points worthy of 
special mention. A female (No. 748 C. A. S.), taken July 25, 
1905, in latitude 19° 40’ N. and longitude 112° W., is im- 
maculate white underneath from bill to crissum; none of the 
Hawaiian specimens I have handled are whiter (plate 17). 
Concealed portions of the dorsal feathers of this specimen are 
more or less washed with gray. In a moulting white-breasted 
male, obtained on October 4, 1906, the general aspect of the 
upper parts is quite gray. The throat in extreme examples of 
the dark phase is not grayer than in four specimens from the 
Kermadec Islands. As in certain other dark-bodied shearwaters, 
the dark gray browns with wear. The feathers of the lower 
parts are white basally in some birds of the dark phase and 
gray in others, the former condition indicating an approach 
toward the light phase. No. 116767 U. S. Nat. Mus., dark 
phase, Kauai Island, Hawaiian Archipelago, also has the 
feathers of the under surface white at the base, especially on 
the breast. Puffinus knudseni Stejneger® was founded on a 
white-breasted bird from Kauai Island, not on a dark-breasted 
one, as implied by Dr. Godman* in quoting from an article’ by 
Mr. A. W. Anthony. Some specimens have gray filoplumes on 
the occiput, cervix, and sides of the head and neck. 
Sern tesrre an tee Mus., v. 2, no. 1, p. 108. 
®Proc. U. S. Nat. Mus., 1888, v. 11, pp. 93, 94. 
*Mon. Petrels, p. 77; cf. Biol. Centr. -Amer., ‘Aves, v. 3, p. 433. 
5 Auk, v. 17, pp. 250, 251. 
