RASORES. 491 



the Grallatores through the Bustards ; and the Megapodidce also 

 appear to have some affinities for the Kails.* 



1 shall divide the Rasores into the following families : — 



A. Hind toe on the same plane as the anterior ones. 



1. Cracidce, Curassows and Guans, peculiar to America. 



2. Megapodidce, Mound-birds, peculiar to Australia and 

 Malayana. 



B. Hind toe raised above the level of the others, or 

 wanting. 



3. Pteroclidce, Sand-grouse, chiefly from Africa and Asia, not 

 extending into Malayana. 



4. Phasianidce, chiefly from Central and Southern Asia. 



5. Tetraonidce, Grouse and Partridges, found over all the world, 

 but rare in Australia and South America. 



6. Tinamidce, mostly American, but sparingly represented in 

 the tropical regions of the Old World, and Australia. 



Blyth does not admit the separation of the Phasianidce and 

 Tetraonidce, and certainly these are more nearly related to each 

 other than either of them are to any of the other families ; but 

 this appears to be always the case with the more typical groups 

 of any order ; and, moreover, the Geographical distribution of 

 each family differs considerably ; for, whilst the Phasianidce are, 

 with one limited exception in America, and that a doubtful 

 member, confined to Asia, and more especially to India and 

 Central Asia, the Tetraonidce are found over all the world, rare, 

 indeed, but not unrepresented in Australia and South America. 

 The fact of certain species of the two families occasionally 

 breeding together, as the Pheasant and Black-grouse (insisted 

 on by some as a proof of the close alliance of these two genera), 

 I consider to be not more anomalous in this order than it could 

 be of two allied genera of another order interbreeding ; and I 

 would regard it simply as an occasional peculiarity in the birds 



* The subject of the external relations and affinities of various groups of 

 animals, though long insisted on by some naturalists, was, till recently, scouted by 

 many ; but the researches and views of Darwin as to the successive development of 

 all created beings, has given a fresh impetus to this interesting subject of enquiry. 



