OSTEOLOGY OF BIRDS 83 



14 The coracoidal grooves of the sternum decussate above the 

 trihedral manubrium ; the xiphoidal extremity of this bone may 

 show one or two foramina in it, on either side, and its border is 

 gently convex forward. 



15 The scapular process of the corocoid does not invariably reach 

 the clavicle. 



16 The humerus is the only pneumatic bone of the wing; there 

 is a mid apical summit to its radical crest; the ulna is 11.5 centi- 

 meters long; there is an os prominens present over the carpus; the 

 digits of manus are devoid of claws, though pollex may possess 

 one. 



17 The femur is the only pneumatic bone of the pelvic extremity; 

 the lowest points of its condyles are in the same plane to which 

 the axis of the shaft is perpendicular; the patella is single; the 

 tibia is one centimeter shorter than the ulna, it has the bony bridge 

 below to confine the extensor tendons ; the hypotarsus of the tarso- 

 metatarsus consists of two separate processes, neither are extended 

 down the shaft; the first metatarsal is a free and large bone, and 

 the arrangement of the phalanges of the digits of pes is upon the 

 most common plan; the long axis of the proximal phalanx of the 

 inside toe is less than half as long as the long axis of the phalanx 

 that next succeeds it. 



Observations upon the osteology of the Kites 



Ictinia, Elanoides, Elanus 

 Compared as a whole, and comparatively speaking, Ictinia 

 mississippiensis has a shorter, wider, and somewhat deeper 

 skull than Circus h u d s o n i u s . Regarded upon its superior 

 aspect it is seen to be not only relatively but actually wider between 

 the orbital margins in the frontal region. The upper osseous man- 

 dible is rather broad and short, with sharp, decurved apex; while 

 the narial openings are far more circular than they are in the 

 harrier. A lacrymal has much the same form, but its supero- 

 horizontal portion is longer and more quadrate at its outer ex- 

 tremity, and the "' accessory piece " is better developed. Practically, 

 it agrees with Circus in the method of its articulation, though from 

 the longer, outflaring superior parts, it appears quite different, and 

 were it only in one piece it would more nearly resemble the lacrymal 

 in the falcons, as it is, it quite closely resembles the lacrymal in some 

 of the Buteos and Falcones that also possess an accessory piece, 

 ligamentously hinged to the outer end. 



