234 MR. W. P. PYCEAPT ON THE MORPHOLOGY AND 



its greatest development rather below the middle of the humerus. There is a feebly 

 developed ectepicondylar process. 



The radiate is well-developed ; the ulnare is reduced to a small nodule. 



In Dromceus, Casuarius, and Apteryx the wing has undergone extreme reduction. 



In Dromceus the length of the whole wing is scarcely longer than the skull. The 

 length of the extended forearm and hand is about equal to the length of the humerus. 

 The manus is considerably shorter than the forearm. There is no distinguishable 

 carpal region, and the radius is anchylosed with the fused carpo-metacarpal mass. The 

 metacarpals and phalanges have all fused into one indistinguishable rod of bone. The 

 pectoral crest is but faintly represented. 



There is a small subtrochanteric fossa, into which opens several pneumatic foramina. 



In the skeleton of I), ater which I have had for examination the wing is 

 wanting. Judging from the measurements given in Milne-Edwards's memoir, how- 

 ever, it seems to have been smaller relatively than in I), novce-hollandice. From the 

 vestigial character of the coracoid grooves one would have expected a much greater 

 difference. 



In Casuarius the wing, strangely enough, though relatively smaller than in Dromceus, 

 is yet less degenerate. The proportions of the brachium, ante-brachium, and manus 

 are much the same as in Dromceus. 



In the adult, the three metacarpals can be plainly made out. That of the pollex 

 is vestigial. Only one phalanx appears to be represented — that of the n. metacarpal, 

 and this is but a vestige. The radiale has anchylosed with the radius, but is still 

 distinguishable. There appears to be no ulnare. The humerus has the pectoral crest 

 more strongly developed than in any other Palceognathce. The subtrochanteric fossa, 

 smaller in Dromceus, is very large in Casuarius. 



In a nestling Casuarius, a radiale, ulnare, and distal tarsal mass are plainly 

 distinguishable. 



In Apteryx the degeneration of the wing has reached a stage somewhat intermediate 

 between that of Dromceus and Casuarius. In the relatively great length of the 

 humerus, however, it differs from both and resembles Rhea. The extended ante- 

 brachium and manus are only a little more than half the length of the humerus. 



The radius is shorter than the ulna. 



The carpus and manus, as both Parker and Beddard have already pointed out, are 

 extremely variable. In A. haastii Parker found an ulnare, radiale, and a fairly distinct 

 rnetacarpale in. In A. australis there are no distinct carpals, but traces are dis- 

 tinguishable of three metacarpals. The index has two or three phalanges, the last 

 terminating in a claw. In A. oioeni the radiale appears to be always distinguishable. 



The manus appears to vary most, according to Beddard, in the matter of degeneracy, 

 in A. australis mantelli. 



In an embryo of Apteryx australis, T. J. Parker found, not only a separate radiale, 



