BIRDS OF NORTH AND MIDDLE AMERICA 473 



Ossifraga Wood, Analyst, ii, No. 11, 1835, 305 (iii, 1836, 199; vi, 1S37, 244; vii, 

 1837, 37). (Type, by original designation, Vultur albicilla Linnaeus.) 



Aetas Morris, in N. Wood's Naturalist, ii. No. 9, 1837, 123. (Types, Ae. 

 pygargus Morris (= Falco albicilla Linnaeus) and Ae. aquila Morris (= Falco 

 chrysnetos Linnaeus.) 



(?) Pontoaeius K.\up, Classif. Saugeth. und Vogel, 1844, 122. (Type, as desig- 

 nated by Sharpe, 1874, Falco leucogaster Gmelin.) 



(?) Poniaetus (emendation) Katjp, Mus. Senckenb., iii. Heft 3, 1845, 261. 



(?) Ponioaetos (emendation) Hartlaub, Index Azara's Apunt., 1847, 1. 



(?) Pontaetos Rey, Syn. Eur. Brutvogel und Gaste, 1872, 255. 



y Haliaeetus Hartert, Vog. pal. Fauna, ii, 1914, 1175.— Peters, Check-list Birds 

 of World, i, 1931, 257 (includes Thallasoaeius). 



Large and powerful "eagles" (wing about 500-712 mm.) with lower 

 half of tarsus nude, the lower half of acrotarsium with several large 

 transverse scutella; no web between basal phalanges of outer and 

 middle toes; feathers of neck (all round) lanceolate, and tail (of 12 

 rectrices), slightly rounded. 



Bill relatively rather large, somewhat inflated laterally, its depth 

 at anterior margin of cere equal to about half the length of culmen, 

 or slightly more; culmen (chord) equal to about half the length of 

 tarsus, regularly and strongly decurved, the tip of maxilla forming a 

 well-developed acute unguis; gonys about one-third as long as culmen, 

 shghtly but distinctly convex; maxillary tomium shghtly but dis- 

 tinctly lobed or festooned a Kttle anterior to lower anterior edge of 

 cere, thence regularly concave to tip of unguis; mandibular tomJum 

 shghtly but distinctly convex for anterior half (more or less), the tip 

 of mandible obliquely truncate; anterior outline of the rather broad 

 cere gently convex in front of nostril, slightly receding and concave 

 below; nostril obhquely vertical, beveled off anteriorly, but not in 

 contact with anterior edge of cere, situated above middle of cere; cere 

 practically straight and horizontal on top. 



Wing long and pointed, the longest primaries exceeding distal 

 secondary b}^ at least one-third the length of wing; third, fourth, or 

 fifth primary longest, the second longer than seventh, the first longer 

 than ninth; inner webs of five to six outer primaries abruptly and 

 deeply emarginated. Tail more than half as long as wing, slightly 

 rounded, the rectrices (12) broadly rounded at tips. Tarsus more 

 than one-eighth as long as wing, robust, densely feathered for about 

 upper half, except on planta tarsi, the middle portion of acrotarsium 

 with several large transverse scutella, elsewhere covered with small 

 roundish, somewhat granular, scales, these larger on upper part of 

 planta tarsi; middle toe about two-thirds as long as tarsus; lateral 

 toes much shorter, the outer decidedly longer than the inner, reaching 

 to about middle of subterminal phalanx of middle toe; hallux about 

 as long as inner toe or shghtly shorter, rather stouter; upper sm-face 

 of toes covered with large transverse scutella, their lower surface 



