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NEW YORK STATE MUSEUM 



cranium by means of an osseous winglike extension. Its tip is free, 

 while I find in the female specimen it is completely fused with the 

 end of the squamosal apophysis, thus including a temporal foramen 

 between them. 



According to Parker this latter state is rather to be regarded as 

 the normal or more constant condition. The squamosal process is 

 here a very thin lamina of bone, laterally compressed, and as in 

 the case of the sphenotic or post frontal one, directed downward 

 and forward. Passing next into the cavity of the orbit, we find 

 the optic foramen large and single, merging as it does, with the 

 corresponding opening of the opposite side. This is also found to 

 be the case with the foraminal aperture for the first pair of nerves ; 

 vacuities may exist, however, on the posterior cranial wall to the 

 outer side of the latter, as they here do in the skull of my female 

 specimen. Beyond these openings the interorbital septum is repre- 

 sented by a thin plate of bone, pierced near its center in the cock's 

 skull by a considerable fenestra, of an irregular outline, while this 

 plate in the hen exhibits only an unbroken surface, as we find it 

 in most Xorth American Tetraonidae. 



Pars plana is found to be entirely in membranocartilage, unossi- 

 fied in the adult while the mesethmoid rises as a thickened pillar, 

 to spread out above, as usual, as an abutment for the overlying 

 frontals and nasals. Posteriorly the orbital wall is smooth and 

 gently arched throughout, being concave in continuation with the 

 concavity of the vault above, which is furnished by the frontal 

 bone. Darwin, when he came to compare the structures to be ex- 

 amined at the base of the skull in the various species of domestic 

 fuwls, was forced to remark that " the bones at the base, from 

 the occipital foramen to the interior end (including the quadrates 

 and pterygoids), are absolutely identical in shape in all the skulls. 

 So is the lower jaw." 1 And. indeed, I fully believe this to hold 

 true with specimens of wild G . bankiva : and so well known 

 now are these several structures that it will be but necessary to 

 touch upon them lightly in the present connection ; the less impera- 

 tive is it, too, as I have taken no little pains in my illustrative ex- 

 hibition of them in figure 4. One thing it will be well to record, 

 however, and we are to note that each and every one of these parts 

 is conspicuous for its slendemess as compared with the correspond- 

 ing structures as we find them in the skulls of most common 

 chickens of barnyard breeding, wherein such bones as the quad- 



1 Darwin, C Animals and Hants under Domestication. Amrr. ed. 1:315. 



