106 



NORTH AMERICAN BIRDS. 



a prominent median angular ridge. Superciliary process of the lachrymal con- 

 sisting of a single piece. {Falconince}) 



B. Scapular process of the coracoid not produced forward so as to meet the 

 clavicle (Huxley). Nasal bones incompletely ossified, the nostrils being very 

 large, and without bony rim or tubercle. Inferior surface of the supramaxillary 

 bone without a median ridge. Superciliary process of the lachrymal variable. 

 (^Accipitrinoti.) 



a. Superciliary process of the lachrymal composed of a single, excessively 

 abbreviated piece ;^ posterior margin of the sternum with a pair of inden- 

 tations, and without foramina. (^Pandion and Nauderus.) 



b. Superciliary process of the lachrymal double, or composed of two pieces, 

 joined by a cartilaginous " hinge," and reaching nearly across the orbit. 

 Posterior margin of the sternum without indentations, and usually with a 

 pair of foramina. (All except Pandion and Nauderus.) 



t Septum of the orbits and nostrils incompletely ossified (the former 

 always and the latter usually) and with foramina ; posterior margin 

 of the sternum most produced backwards laterally, and incompletely 

 ossified, there being usually a pair of foramina. Intestinal canal short, 

 broad, with the duodenum simple, forming a single loop (McG-illvray). 

 A well-developed " web " between the outer and middle toes. (All 

 but Halicetus.) 



tt Septum of the orbits and nostrils completely ossified, and without 

 any trace of foramina ; posterior margin of the sternum produced 

 medially into a convex lobe, and without any trace of foramina. In- 

 testinal canal extremely elongated, attenuated, with the duodenum 

 arranged in several convolutions (McGillvray). No trace of a web 

 between outer and middle toes. {Halicetus.) 



Subfamily PALCONIN-aE. 



Genus FALCO, Auct. 



G-EN. Char. Bill strong, its breadth at the base equalling or exceeding its height; 



upper outline of cere on a level with, or rather lower than, the base of the cul- 



men ; gonys much arched, the chord of the arch equalling 

 about half that of the culmen. Near tlie tip of the upper 

 mandible is a prominent tooth on tlie commissure, and near 

 the end of the lower mandible, which is truncated, is a 

 deep notch corresponding ; the end of the upper mandible is 

 compressed, giving the situation of the tooth an inflated appear- 

 ance when viewed from above. Nostrils circular, with a con- 

 spicuous central tubercle. Orbital region bare ; projecting 

 superciliary shield conspicuous, arched, but not very prominent. 

 Tail shorter than wing, the feathers hard and stiff. Primaries 

 very strong, elongated, tapering rapidly toward their points; 

 only the first or first and second with their inner webs emar- 

 ginated, the cutting being angular, and near the end of the 



quill. Tarsus never with a single series of transverse scutellse either in front or behind ; 



middle toe very long. 



13077, ? 



1 Embracing besides the Falcones all the Polyborine genera, besides Herpctotheres and Micrastur. 



2 As in the Polvborine forms of the Falconince. 



