478 STEUCTUEE AND CLASSIFICATION OF BIEDS 



hawks, for example in Haliaetus albicilla, Lophoaetus occipi- 

 talis. Circus Goulcli, Asturina Natteri, Astur Novcb Hol- 

 landice; in others, such as Herpetotheres cachinnans, Vultur 

 calvus, the large size of the lacrymal suggests that such a 

 bone is present, but ankjlosed with the lacrymal. The bony 

 nostrils of the Falconidas are holorhinal, sometimes (e.g. 

 Herpetotheres cachinnans) reduced in extent by alinasal 

 ossifications ; the long septum between them is more or less 

 perfect. The number of cervical vertebrse, ribs, hsemapophyses, 

 and uncinate processes of a few types is shown in the fol- 

 lowing table : — 



The sternum is whole or with one pair of foramina, some- 

 times notches, and often only developed on one side. The 

 coracoids slightly overlap in Dryotriorchis, Herpetotheres, 

 and Melierax ; they do not quite meet in Accipiter, Lopho- 

 aetus, &c. 



Pandion is undoubtedly an aberrant genus, which is by 

 several (e.g. Gadow) made the type of a separate family, and 

 is thought by some to lead towards the owls. It differs from 

 other falcons in having no aftershaft, in its somewhat 

 peculiar tensores patagii and deep plantar tendons. 



The tensor patagii brevis has the additional ' aquiline ' 

 wristward slip, from the middle of which rises a short 

 recurrent slip which joins the insertion of the main tendon. 

 The tendon of the biceps muscle is split for nearly its whole 

 length. 



The deep plantar tendons are not accipitrine ; they blend 

 completely, as in owls, hornbills, &c., the area of fusion being 

 ossified. 



