SKELETON OE PHOEOEHACOS 1NFLATUS. 71 



only slightly grooved at its posterior end ; there is no fossa into which the cuneiform 

 fits when the manus is flexed upon the forearm ; the so-called pisiform process is 

 almost absent. The prominence formed by the fused first metacarpal is stout and 

 short, and terminates in a roughened surface which may possibly have formed the base 

 of a short horny spur or knob. Distally the first metacarpal terminates in a tubercle 

 for articulation with the phalangeal. The second metacarpal (me. 2) is short and 

 thick, compressed laterally and slightly curved. On its upper surface there is a nearly 

 longitudinal, faintly marked groove, and on the anterior surface of the distal end is 

 another short groove for tendons. 



The third metacarpal (mc. 3) is much more slender than the second; it is strongly 

 curved and so compressed that it forms a mere band of bone. On its ventral surface at 

 the proximal end is a prominent tubercle (t.), which will be referred to below ; distally 

 it is fused with metacarpal 2 in the usual manner. The distal extremities of the fused 

 metacarpals bear each an articular surface for their phalangeals, as in most birds. The 

 length of the metacarpus is 76 mm. 



The reduction that has been undergone by the bones of the wing makes their 

 comparison with those of other birds difficult. 



The distal portion of the humerus differs widely from the Albatross, in which the 

 impression of the brachialis anticus is in a different position and there is a large 

 ectepicondylar process. In the Birds of Prey the depression on the anterior face above 

 the articular surfaces is always much less than in Phororhacos, and the impression 

 of the brachialis anticus is more median ; in some the distal border is somewhat oblique 

 and there is a trace of the distal process. 



In Ciconia the distal border is not oblique and the position of the brachialis impres- 

 sion is quite different. 



In Grus the differences are the same as in Ciconia. 



In both Cariama and Psophia also the distal border is only slightly oblique (in 

 Cariama there is a trace of a blunt distal process on the ulnar side). 



The humerus to which I find most resemblance in the form of the distal end is that 

 of Diaphorapteryx, the large extinct Eail of the Chatham Islands. In this the distal 

 border is oblique, there is a fairly prominent distal process, and the form and position 

 of the brachialis anticus impression is similar. The humerus of Aptornis is also some- 

 what like the fossil, but in it reduction has gone further, the division between the radial 

 and ulnar condyles being still more indistinct and the distal process small. 



The short, stout ulna is not very much like that of any of the birds referred to in the 

 comparison of the humerus, but approaches that of Psophia most nearly. 



The proximal end of the right radius is preserved. Its articular surface is oval in 

 outline, and the bicipital tuberosity is strongly developed. It is almost identical with 

 the same element in Cariama, but the characters of the radius are not sufficiently different 

 in the various groups to be of much importance in determining affinities. 

 vol. xv. — part in. No. 3. — October, 1899. m 



