1046 SYSTEMATIC SYNOPSIS.— PYGOPODES. 



F. gralla'ria. (Lat. for grallatorius, relating to stilt- walking; grallator, one who goes on 

 stilts; grallce, stilts, related to gradus, a step, stride, pace.) Lawrence's Stilt Petrel. 

 White-bellied Petrel. Adult : Blackish of variable intensity, blackening on quills and 

 tail, lightening to grayish on back, where the feathers may be edged with whitish; abdomen, 

 upper tail-coverts, most under wing-coverts, and bases of all tail-feathers except middle pair, 

 white; bill and feet black. Length 7.50-8.00; wing 6.00-6.50; tail 3.00, about even, with 

 very broad, square-tipped feathers; bill 0.50; tarsus 1.33; longest toe (outer) and claw 1.00 

 or less; tibiae bare 1.00 or more. Southern seas; Florida, accidental, one instance (Lawr. 

 Ann. Lye. Nat. Hist. N. Y. 1851, v, 117). 



PELAGODRO'MA. (Gr. ntXayns, x>elagos^ the sea ; 8p6fios, dronios, running.) Clipper 

 Stormy Petrels. Resembling Fregetta in great length of leg, fiat, blunt claws, and other 

 characters. Basal phalanx of middle toe not peculiar ; tarsi appreciably scutellate. Bill re- 

 markably long, slender, and compressed, with weak hook and short nasal tubes, less than half 

 as long as culmen. Wings of moderate length, folding just beyond end of tail; 2d primary 

 longest, 3d nearly as long, 1st about equal to 4th. Tail long, square, or but slightly emar- 

 giuate, with broad feathers, truncate at the end. Tibiae bare an inch or more; middle toe and 

 claw nearly as long as tarsus; webs very full. One species. 



P. mari'na. (Lat. marine.) White-faced Petrel. Color ashy-gray, or slaty, of vari- 

 able shade, blackening on wings and tail, lightening on back, rump, and upper tail-coverts, 

 where the feathers may be edged with white; all the under parts, the forehead, and line over 

 eye, white. Bill and feet black ; webs mostly yellow. Length about 8.00; wing 5.80-6.20 ; 

 tail about 3.00, emarginated about 0.30; bill 0.90; tarsus LOO; middle toe and claw 1.40. A 

 large, handsome species, the original "Frigate Petrel" of Latham, related to Fregetta gral- 

 laria, but readily distinguished. Southern seas, N. to the Canary Islands; accidental in Great 

 Britain (Walney Island in Morecanjbe Bay, Nov. 1890, and Colonsay Island, W. coast of 

 Scotland, Jan. 1, 1897) ; once taken off the coast of Massachusetts, lat. 40° 34' 18" N., long. 

 66° 09' W. Auk, Oct. 1885, p. 386; Ridgw. Man. N. A. Birds, 1887, p. 72; Coues, Key, 

 3d ed. 1887, p. 893; A. 0. U. List, 2d ed. 1895, p. 38, No. [111.] 



Order PYGOPODES: Diving Birds. 



In 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 trav- 

 ersing great distances under water, progress being effected by the wings as well as by the feet. 

 Few other birds, as Cormorants, Anhingas, Penguins, and the passerine Dippers, resemble 

 Pygopodes in this respect. The legs are so completely posterior, that in standing the hori- 

 zontal position of the axis of the body is impossible ; the birds rest upright or nearly so, the 

 whole tarsus being often applied to the ground, while the tail affoi-ds additional support; pro- 

 gression on land is awkward and constrained, only accomplished, in most cases, with a shuffling 

 motion, when the belly partly trails on the ground. One species of Auk could not fly at all, 

 because the wings, although perfectly formed, were too small to support the body. The rest 

 of the order fly swiftly and vigorously, with continuous wing-beats. The rostrum varies in 

 shape with the genera; but it is never extensively membranous, nor lamellate (as in Anseres 

 and some Tubinares), nor furnished with a pouch (as in most Sfeganopodes) ; nor are the 

 tomia ever serrate. The nostrils vary, but are neither tubular nor abortive. The wings are 

 short, never reaching when folded to end of tail, which is short, never of peculiar shape, gen- 

 erally of many feathers (there are, however, no perfect rectrices in Grebes). The crura are 

 almost completely buried, and feathered nearly or quite to the heel. The tarsus is usually 

 compressed; sometimes, as in Loons, extremely so. The front toes are completely palmate 



