Vou. 11, Pt. 11] LOOMIS—A REVIEW OF THE TUBINARES 125 
when they clear the water and are fairly a-wing. When 
feeding in windy weather, they often alight ‘for a moment 
without closing their wings. One proved himself well worthy 
of the name of petrel while picking up food during a brisk 
wind. He would poise for a moment, with wings outspread 
and feet just touching the water, and then dart to the wind- 
ward for a few feet without flapping his wings, which ap- 
parently served the same purpose as “the sails of a. vessel 
when close-hauled on the wind.’ On another occasion a 
flock of about thirty while feeding would fly slowly to the 
windward for a few rods, keeping close to the water, and 
then turn and fly swiftly back to the starting point and 
repeat the maneuver. In calm weather they collected in 
flocks on the water while feeding. On one occasion the birds 
of a company were continually putting their heads under 
water and when something edible was discovered they would 
dive, often remaining beneath the surface for a full minute. 
The remains of small crustaceans were found in the stom- 
achs of several birds taken from nesting holes on Hood 
Island in February. One day a number were flying about a 
brigantine at Villamil, Albemarle Island, apparently attracted 
by the droppings from the cattle that were being hoisted 
aboard. 
Galapagos examples of this species exhibit considerable 
variation, and on the strength of certain features of this varia- 
tion Mr. Gregory M. Mathews has endeavored to separate the 
birds of Culpepper and Wenman islands from those of the 
rest of the archipelago, holding that the former are larger and 
that their under wing-coverts and axillaries are less dusky.* 
As the Expedition males yielding the maximum measure- 
ments are from Hood Island and as certain specimens from 
that island have white under wing-coverts and axillaries, it is 
evident that Mr. Mathews has mistaken other variations for 
geographic variation. 
The under wing-coverts and axillaries vary in general 
aspect from immaculate white to dark gray. The former 
extreme is typically represented in the Expedition series by 
No. 837, male, February 6, No. 859, male, May 21, No. 885, 
female, June 25, and the latter extreme by No. 839, male, 
1 Birds Austr., v. 2, pp. 62, 70. 
