OSTEOLOGY OF BIRDS 



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also true in the case of Cuculus. The thin " radial crest " is semi- 

 circular in outline, and consequently terminates abruptly on the 

 shaft. At the distal end of the bone, we find an " ectocondyloid 

 tubercle " to be present, as in other cuckoos. The ulna exhibits 

 but moderate curvature down its shaft along which we find some 

 six papillae for the butts of the quills of the secondary feathers. 

 The radius is unusually straight, slender, and of nearly uniform 

 caliber in so far as its shaft is concerned. Carpal elements, the 

 usual two, are large, and as in the case of the other bones of 

 manus have much the same character, barring curvature, as the 

 corresponding ones in Geococcyx, including the peculiar little 

 process, for tendinal insertion, on the posterior margin of the distal 

 phalanx of the medius digit. No claws appear to be present on 

 any of the fingers, so far as I have been able to discover. 



Cuculus has a wing skeleton that in its characters closely re- 

 sembles that of Coccystes, but the long bones are comparatively 

 stouter and shorter. The distal phalanx of the hand exhibits a 

 groove for its entire length posteriorly, which in life is coextensive 

 with the concavity occupying the entire outer aspect of the phalanx 

 above it, that is, the proximal joint of the index digit, an unusually 

 broad one on its anterior surface. 



In Coccystes the humerus has a length of 4.7 centimeters ; an 

 ulna of 4.6 centimeters; and a carpometacarpals of 2.5 centimeters — 

 the index digit (two joints) also 2.5 centimeters. The same 

 bones in Cuculus c a n o r u s measure 4.2 centimeters, 4.2 

 centimeters, 2.2 centimeters, and 2.2 centimeters respectively. 



Pelvic limb. None of the bones of the skeleton of the leg inCoc- 

 cys-t.es g 1 a n d a r i u s are pneumatic, and their shafts exhibit 

 but very slight curvature, that of the metatarsus being quite 

 straight. In the femur the trochanter does not rise above the shaft 

 or summit of the bone, while at the distal extremity, anteriorly, the 

 intercondyloid groove is narrow and deep. In Coccystes the patella 

 is a small and very insignificant sesamoid, a condition that obtains 

 in all of the small cuckoos examined by me. 



At the pfbximal end of tibiotarsus we note that the cnemial proc- 

 esses are much reduced, and do rise above the summit of the bone, 

 the entocnemial one being the better produced. As a whole the 

 shaft of this leg bone is very slightly bowed to the front, and below 

 the " fibular ridge " is cylindrical in form. Distally, its condyles are 

 well developed, with a deep intercondyloid valley between them, an- 

 teriorly. Much reduction has taken place in the fibula; which is 



