AND DEVELOPMENT OF THE BIRD'S SKULL. 141 



My views as to these relationships were fairly pledged several years since (see " Gal- 

 linaceous Birds and Tinamous," Trans. Zool. Soc. vol. v. p. 150) ; and I was soon led to 

 see how many large Families of Birds were constructed according to the pattern of the 

 Plover*. 



But this was only one among several nascent generalizations germinating in my head 

 at the time ; so that when Prof. Huxley's new ideas were given out, they fell into a recep- 

 tive soil, so far as I was concerned. 



In this, as in other branches of zoology and morphology, there has been for many 

 years a remarkable harmony in our views ; and nothing more struck and delighted 

 me, in that coincidence, than my friend's commendation of one of the large groups 

 that seemed to me to gather towards one point : I refer to the double " Gallo-Anserine" 

 family. 



That the embryology of both the Goose and Powl was marvellously similar, I had then 

 seen ; but I was not aware how close the Palamedeas on one hand come to the 

 Curassows and mound-making Megapods on the other. 



But that which concerns us most at present is the huge number of birds with open 

 palates (" Schizognathse ") that have either a filial relationship to the Plover, or are 

 cousins-german to it. 



It thus comes to pass that when once the structure of a Plover's skull is thoroughly 

 understood, it serves as a norma to which the skulls of whole groups of birds can be 

 brought for comparison. 



This is true, not merely of the related Schizognathous birds, but also of those Grallse 

 which are desmognathous ; for the likeness and the difference between the split skull 

 Of a fowl and the bound skull of a Palamedea is very similar to the likeness and the 

 unlikeness of the skull of the Crane on the one hand, and of the Heron and Stork on 

 the other. 



There is one thing which is apt to mislead the zoologist in the consideration of the 

 great group of "Carinate" birds; they, with the "Batitse," are unconsciously compared 

 with the whole of the Mammalia. At first view it might be thought that the Batitas 

 equalled, as a group, the " non-placental " mammals, and the Carinatse the placental; 

 but the groups are not properly comparable ; the Carinate birds, notwithstanding their 

 number and variety, could not be equalled with more than two or three at most of the 

 Mammalian Orders, and not with the whole herd of the Placentalia. 



Those morphological modifications which lie at the root of the diverse specializations 

 of the Carinate birds take place, as we pass from type to type, in the gentlest manner ; all 

 the types of skull may be seen to spring from a fundamental form, rich in Bhyncho- 

 saurian, and even in Batrachian characters. Such a skull the Batitse all possess. 



After analyzing a skull of this kind, and finding how it is built up, as it were, accord- 

 ing to old styles of skull-architecture, familiar to him who knows the lower or cold- 

 blooded types, the morphologist is brought to a stand ; for here the lines of life diverge. 



* This, was handled excellently by Prof. Huxley in his " Classification of Birds" (Proc. Zool. Soc. 1867, pp. 426- 

 431 and 456-458). 



U 2 



