30 SHUFELDT — OSTEOLOGY OF THE CUCKOOS. [Jan. 4, 



special examinations as to the condition of the ossifications of the 

 columella auris in the adult Geococcyx. I find, however, among 

 other normal ossifications in this type some twelve or thirteen 

 sclerotal plates in either eye, overlapping each other in a somewhat 

 irregular manner. As in certain other birds, some of the tendons 

 of the pelvic limb in old individuals of this Cuckoo are converted 

 into bone, and small sesamoids may be found about the proximal 

 extremities of the basal joints in the soles of the feet. The entire 

 skeleton of the pelvic limb for Geococcyx is figured in my former 

 memoir in the Journal of Anatomy. 



OSTEOLOGICAL NOTE UPON THE YOUNG OF GEOCOCCYX CALIFOR- 



NIANUS. 



My collection contains the skeleton of the nestling of the Cuckoo 

 now under consideration, secured at the time immediately before 

 the bird quits the nest. This skeleton is disarticulated, and, like 

 all the skeletons of immature birds, offers a very instructive object 

 for study. 



Several years ago, as I have said in the Introduction above, I 

 published in the London Journal of Anatomy (Vol. xxi, p. 101) an 

 observation upon the tibio-tarsus of the pelvic limb to this skeleton, 

 and the substance of these remarks with addenda are herewith 

 incorporated. 



It is a well-known fact that the proximal extremity of the tibio- 

 tarsal shaft is much larger and more bulky in the young of certain 

 birds than it is in the adults of the same species. 



This is very appreciably the case in many Gallinaceous fowls, and 

 I have already remarked upon it as a striking feature in the skeleton 

 of the young of Centrocercus tirophasianus ; while in our present 

 subject, this immature Geococcyx, this condition obtains to an 

 extent unequaled, so far as my observations go, by any of the 

 GallincE. 



Further, that portion of the tibio-tarsus, which in the old bird 

 eventually becomes the antero-superior part of the shaft, and sup- 

 ports the pro- and ectocnemial processes, is in the young individual 

 developed as a separate epiphysis. Formerly, from careful exami- 

 nation of material, it appeared to me that this epiphysis was super- 

 added to the true epiphysis of the summit of the shaft of this bone of 

 the leg, and thus corresponded to the olecranon of the ulna. (See 



