OF GALLINACEOUS BIRDS AND TINAMOUS. 235 



noids, the pterygoids, palatines, os quadratum, and os articulare, all these agree in 

 everything essential, even in the adult bird. 



But, more than this, the wrappings of the mandibular rod, much as they differ ante- 

 riorly in the two groups, yet agree behind in the peculiar sickle-like process to the 

 " angular " splint bone. 



An extended embryology will largely influence the systematic arrangement of birds ; 

 for it will open our eyes to the essential unity often underlying the uttermost degree of 

 polymorphism, whilst the veil will be torn from those mimetic isomorphs which have so 

 long deceived those ornithologists who look mainly at outward appearances, but do not 

 penetrate to the heart of the matter. 



As the relationships of the Gallinaceous subfamilies are very intricate, I shall append 

 a few schemes, showing the comparative nearness of certain main genera ; these will, 

 of necessity, be the merest diagrams, and will represent the fu'ness of the subject just 

 as the first sketch of an artist, when he has thrown in the outline of the trunk and of a 

 few of the main branches, represents the fulness of a noble tree. 



I will first show, in two parallel columns, how both the Fowls and the Rails run 

 insensibly through certain leading genera into the lowest (reptilian) types of diving- 

 birds. 



Notornis. Gallus. 



IBrachypteryx. Crax. 



Ocydromus. Talegalla. 



Tribonyx. Palamedea. 



Crex. Anseranas. 



Rallus. Plectropterus. 



Gallinula. Anser. 



Porphyria. Anas. 



Fulica. Fuligula. 



Podilymbus. Harelda. 



Podiceps. Biziura. 



Podica. Merganser. 



Aptenodytes. Phalacrocorax. Colymhus. Alca. 



But the Plovers {Charadrius, Pluvialis) stand in the centre of large groups of genera, 

 many of which are nobler (more ornithic) than themselves, and not a few of which are, 

 notwithstanding their elevation above the simple and very reptilian Plovers, quite true 

 to that type. These latter are the Ibises on one hand, and the Gulls on the other : 

 these latter birds, be it remarked, ascend in the bird-scale, in spite of their marine habits 

 and although they never become quite fissiped. In the following list the central birds 

 are the lowest in type : — 



