332 



PYGOPODES, DIVING BIRDS. 





2 J. North Atlantic, alniiidant; S. at least to Carolina {Cones). A special 

 state of P. major? Strickland, Proc. Zool. Soc. 1832, 129 ; DeKay, 

 New York Birds, 287, pi. 136, f. 298; Lawr. in Bd., 834; Coues, 



^"^S<g^ Proc. Phila. Acad. 1864, 



123. . EULIGINOSUS. 



Dark-bodied Shear- 

 umter. Similar to the 

 last ; feet flesh color, 

 slightly obscured out- 

 side ; lining of wings 

 mostly white ; smaller ; 

 Fig. 212. soory si.niH ,iei wingll,etc. Cape St. 

 Lucas. Very doubtful. I allow this, and several others, to stand, because 

 it is still uncertain what reduction of the species of this genus will prove 

 necessary. JVectris amaurosoma Coues, I. c. 124. . . . amaurosoma. 

 Slender-billed Shearwater. Plumage as in the foregoing ; size less ; tail 

 shorter; bill smaller. Bill dusky-greenish, with yellow; feet yellowish, 

 blackish behind and under the webs. Length about 14 ; wing 10 ; tail 

 3 J, graduated an inch ; bill 1^ ; tarsus under 2 ; middle toe and claw 2J-. 

 N. Pacific Coast. Temm., Planches Color. No. 587 ; Temm. and Schl., Fn. 

 Japon. 131, pi. 86; Bonap., Consp. Av. ii, 202; Coues, I. c. 126; Baird, 

 Trans. Chicago Acad, i, 1869, 322, pi. 34, f. 2. P. tristis, curilicua and 

 brevicauda of authors? tenuirostris. 



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 as by the feet. Few other birds, such as cormorants 

 and anhingas, resemble the Pygopodes in this respect. The legs are so completely 

 posterior, that in standing the horizontal position of the axis of the body is impos- 

 sible ; the birds rest upright or nearly so, the whole tarsus being often applied to 

 the ground, while the tail aflfords additional support ; progression on land is awkward 

 and constrained, only accomplished, in most cases, with a shuffling motion, when 

 the belly partly trails on the ground. The penguins, and one species of auk, cannot 

 fly — the former, because the wings are reduced to mere flippers with scaly feathers, 

 the latter because the wings, although perfectly formed, are too small to support 

 the body. The rest of the order flj^ swiftly and vigorously, with continuous wing- 

 beats. The rostrum varies in shape witii the genera ; but it is never extensively 

 membranous, nor lamellate, nor furnished with a pouch. The nostrils vary, but are 

 neither tubular nor abortive. The wings are short, never reaching when folded to the 

 end of the tail, and often not to its base. The tail is short, never of peculiar shape, 

 generally of many feathers ; there are, however, no perfect rectrices in the grebes. 

 The crura are almost completely buried, and feathered nearly or quite to the heel. 

 The tarsus is usually compressed, sometimes, as in the loons, extremely so ; in the 

 penguins, on the contrary, it is much broader across than in the opposite direction, 

 being nearly as wide as long. The front toes are completely palmate in the loons, 



