102 



NEW YORK STATE MUSEUM 



convex surface of the fellow of the opposite side, while in front 

 both of these maxillopalatine scrolls fuse indistinguishably with the 

 nasal septum. 



Another excellent character is to be seen in the low, sharpened 

 mediolongitudinal ridge, which, upon the buccal aspect of the pre- 

 niaxillary extends from the apex of the beak, backward to the an- 

 terior border of the nasoseptal mass. This is usually a gutter or 

 groove in the same locality in all the eagles, and other buteonine 

 hawks and kites. With these true falcons, too, we find the an- 

 terior surfaces of the ethmoidal wings (pars plana) and the anterior 

 border of the mesethmoid lying roughly in the same plane, and it is 

 only below, that the rounded apex of the rostrum slightly projects 

 beyond this surface. In the Buteos, eagles and most kites the an- 

 terior border of the mesethmoid is carried beyond the pars plana, 

 and it may be either sharpened or rounded. 



A small ramal vacuity exists upon either side in the mandible of 

 Falco mexicanus, but it is absent in another of this genus, 

 namely Falco r. gyrfalco. The bone agrees in its general 

 pattern with the lower jaw of the eagles and others, but is relatively 

 shorter ; it is also peculiar in developing distinct little processes to the 

 outer side, and rather in front of either articular cup, which pro- 

 cess curves backward, and when the jaw is in situ, articulates with 

 the outer aspect of the quadrate. This articulation is just below, 

 though rather in front of, the quadratojugal articulation. In eagles 

 and buzzards this character is but feebly developed. 



Nothing of special interest characterizes the ossifications of the 

 eye, ear, or hyoidean apparatus, other than has been set forth above 

 for the Falconidae in general. In the eye of Falco mexi- 

 canus we find at its back, a thin bony circlet surrounding the 

 entrance of the optic nerve. Very probably it occurs in all birds of 

 this suborder, and is often met with in others of the class (Corvidae, 

 Pici etc.). 



Except in the matter of size, they being larger birds, the gyr- 

 falcons agree in the characters of their skulls and associated ossifi- 

 cations with the corresponding structures in Falco mexi- 

 canus. 



Often Falco sparverius has the supraorbital part of 

 either lacrymal drawn out into more or less of a point, and in this 

 little hawklet the narial apertures are quite circular with the ali- 

 nasal nib of the turbinal (alinasal) there exposed, situated directly 

 at the center. 



