Falcomile.] 



OSTEOLOGIA AVIUM. 



[Falcontn^e. 



Falco, Linn. 



Gyrfalco, Linn. 



I have only the sternum of this bird, which does not differ from that of Falco pere- 

 grinus except in size, and in the keel being deeper in proportion to the breadth of the 

 sternum. 



Since the above was written, I have obtained, from a skin, the head, wing, and leg 

 bones of this bird, and find them also not distinguishable from those of F. peregrinus 

 except in size and proportions. 



Measurements. 



Tenths. 

 Breadth of posterior margin of sternum 2 2 

 Breadth of anterior margin of sternum 17 

 Depth of keel 11 



Tenths. 



Length of humerus 44 



Length of ulna 50 



Length of metacarpus 28 



Length of femur . - 



Length of tibia 44 



Length of metatarsus 26 



Length of sternum 35 



Length of head 30 



Breadth of head 21 



Length of pelvis 



Breadth of pelvis 



Falco, Linn. 



Aurantius, Lath. 



The skeleton of this bird does not differ, except in measurements, from F. peregrinus ; 

 the sternum is somewhat longer in proportion to its width. 



Measurements. 



Tenths. 



Length of humerus 16^ 



Length of ulna 19 



Length of metacarpus 11 



Length of femur . . . . . . 15 



Length of tibia . 22 



Length of metatarsus 14 



Length of sternum ...... 14 J 



Tenths. 

 Breadth of posterior margin of sternum 9 

 Breadth of anterior margin of sternum 

 Depth of keel . 

 Length of head 



Breadth of head 

 Length of pelvis 

 Breadth of pelvis 



7 



4 



18 



10 



17 



9 



Herpetotheres, VieilL 



Cachinnans, Linn. 



The cranium agrees with Falco peregrinus in its great breadth in proportion to its 

 length, in the shape of the palatine bones, and in the septum being perforated by one 

 central foramen; the nasal orifices are also round and small, with the upper margin 

 slightly projecting; the lacrymal bones are similar, but rather broader. The tarsi 

 agree with Falco. 



b2 . 3 



