PMOCELLAHIIDJE : PMOCELLAMIIN^ : SHEARWATERS. 787 
blackish, except a few of the shortest just at the vent. More dark color on flanks, on lining 
of wings and axillars than in obscurus. In the dry state, bill yellowish or reddisli-brown, the 
nasal tubes and cuhnen blackish, the hook mostly bluish-white. Outside of tarsus for the 
most part, outer toe and edges of webs, blackish ; rest of foot pale yellowish flesh-color; ''iris 
brown." Wing about 9.00; tail 3.75, graduated 0.60 ; tarsus 1.80 ; middle toe and claw 2.10 ; 
chord of culmen 1.40; gape 2.00; end of nasal tubes to tip 1.05 ; height at base 0.42, at hook' 
0.32. Cape St. Lucas, L. Cala. Decidedly different from P. obscurus. (P. gavia Forst. ?) 
837. P. fuligino'sus. (Lat. fuliginosus, sooty. Fig. 528.) Sooty Shearwater. Very different 
from any of the foregoing. Nearly uniform dark sooty-brown, blackening on quills and 
tail-feathers, more sooty-gray below, paler still on the throat ; lining of wings mixed sooty 
and whitish. Bill drying an 
undefinable dark color, in life 
dusky bluish-horn color, the 
tube, ridge, and hook black- 
ish ; feet drying dark outside, 
pale inside ; in life the inside 
of tarsus and upper side of feet 
livid flesh -color, the outside of 
outer toe and under side of 
feet blackish ; eye blackish. 
Length about 18.00, rather 
less than more; extent about 528. - Sooty Shearwater, nat. size. (Ad nat. del. E. C.) 
40.00; wing 12.00; tail 4.00; tarsus 2.25; middle toe and claw 2.50; chord of culmen 1.75- 
2.00; gape 2.33 ; feathers on side of lower mandible to tip 1.67; depth of bill in front of nasal 
tube 0.40. A wide-ranging species ; common off our Atlantic coast, especially northerly. It 
is perfectly distinct from any of the two-colored species, of several of which it has at times 
been considered to be the 9 or a special state of plumage. Breeds in colonies, often of great 
extent, laying a single egg in holes burrowed several feet deep in the ground. 
838. P. amauroso'ma. (Gr. dfxavpos, amauros, dark; aafxa, soma, body.) Dark-BOdied 
Shearwater. Similar to the last, from which perhaps not specifically distinct. Under 
wing-coverts white, only interrupted by some dusky marbling. Bill (dry) brownish- black, 
horn-colored at tip. Feet (dry) light yellowish flesh -color, tinged with brown (m outside of 
tarsus, outer toe, and tips of claws. Smaller: wing 11.00; tail 4.25, graduated 0.90 ; tarsus 
2.00; middle toe and claw 2.40 ; outer do. 2.30; chord of culmen ].70. Cape St. Lucas, 
Cala. 
839. P. tenuiros'tris. (Lat. tenuis, slight, thin ; rostrum, beak.) Slender-billed Shear- 
water. Distinct : a small, weak-billed, short-tailed, very dark-colored species, sooty-black 
above, quite black on quills and tail-feathers, beneath smoky-gray, palest on throat, the 
under tail-coverts nearly as blackish as the upper parts. Groove of under side of primary- 
shafts yellow. Bill (dry) dusky greenish-yellow, brighter along edges and at tip ; feet (dry) 
yellowish, the hinder edge of tarsus and under surface of webs blackish. Length about 
14.00; wing 10.00; tail 3.50, graduated 0.75; chord of culmen 1.20; depth of bill at base 
0.30; width 0.40; tarsus 1.90; middle or outer toe and claw 2.25. N. Pacific, Sitka to 
Japan. 
XIII. Order PYGOPODES: Diving Birds. 
In the birds of this order the natatorial plan reaches its highest development. All the 
species swim and dive with perfect ease; many are capable of remaining long submerged, 
and of traversing great distances under water, progress being effected by the wings as well 
