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XXIX. On the Structure and Development of the Skull of the Common Fowl (Gallus 
domesticus). By William Kitchen Parker, F.R.S. 
Received November 25, 1868. — Read February 11, 1869. 
Introductory Remarks. 
In my former paper, which treated of the structure and development of the skull in the 
Ostrich-tribe*, I proposed to write a series of such papers on the skull of the Verte- 
brata, and that the first of these should be confined to that of the Common Fowl. 
This Bird is selected for several reasons, the first of which is the readiness with which 
it may be obtained ; but, as far as science is concerned, a still more important reason 
lies in the fact that it not only forms a good halfway subject between the Ostrich and 
the Singing-bird, but, in a wider survey, it serves as an excellent stand-point from which 
to look backward to the Fish, and forward to the higher Mammalian forms. 
The present paper is much more special than the last, which treated of the skull of 
several kinds of Struthious Birds, in just as many stages as I was able to obtain : this 
time an essay has been made to describe, step by step, the whole process of growth of 
the skull, face, and sense-capsules from the fourth day of incubation to extreme old age. 
My reason for not describing the earliest stages is, that I find it done to hand 
already ; and although I have repeatedly verified the observations of other authors on 
the primary condition of these parts, yet I have nothing more to add to what is already 
known. The latest and best description that I have seen of the primordial condition of 
the head of the chick is to be found in Professor Huxley’s ‘ Elements of Comparative 
Anatomy,’ pp. 136-142, and figs. 57 A-G. 
My starting-point is at that stage which is the last but one in Professor Huxley’s 
series — namely, figs. 57 F and F' (p. 138); my second stage agrees with his fig. 57 G. 
In describing the Struthious skull, I did not depend merely upon what an examination 
of those types revealed, but had already made a large number of observations (and 
drawings) on the development of the skull in various Families of Birds, and also in many 
types from the other Vertebrate Classes. It was shown me, however, by my most 
judicious friend, Professor Huxley, that my work missed its end, in some degree, from 
its diffuseness, and that it would be better to get a perfect history of one type of skull, 
than an imperfect knowledge of any number whatever. So, to be thorough, it must 
content me to cultivate a small and modest plot at one time, trusting in the Unity of 
Nature for the value of the results, and confident that, if I can read the meaning of the 
Fowl’s skull, my eyes will be opened to see very much more, below, above, and around. 
* Philosophical Transactions, 1866, vol. clvi. part 1. pp. 113-183, pis. 7-15. 
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