PHYLOGENETIC 51 



which are divisible into two groups, according to the structure 

 of the feet — A. Peristeropodes, B. Alectoropodes. In the first 

 the hallux is large, and arises low down the metatarsal shaft, 

 so that all four toes are on the same level ; but besides this 

 the skeleton displays less specialisation than is met with in 

 group B., and this applies more especially to the sternum, 

 shoulder and pelvic girdles. 



Probably the most lowly of the Peristeropod forms are the 

 Megapodes of the Austro-Malayan region. They are generally 

 regarded as forming a distinct Family, the Megapodiidae, while 

 a second Family is made up of the Cracidse — the Curassows 

 and Guans of Central and South America, comprising some 

 four genera and fifty species in all. 



The group Alectoropodes embraces all the remaining 

 Gallinaceous birds, which may well be included in a single 

 Family divided into sub-Families, though this practice is not 

 generally followed, the custom being to form several Families, 

 and to divide these again into sub-Families. The more im- 

 portant types herein embraced are the Turkeys, Guinea-fowls, 

 Grouse, Partridges, Francolins, Quails, Pheasants and Peacocks. 



Anatomically the Galliformes are a very sharply defined 

 group, and on this account it is curious that the Tinamous 

 should so persistently be associated therewith, though this is 

 generally done by those systematists who are guided only by 

 superficial characters. As we have already shown, these birds 

 should probably be regarded as Palaeognathae, though this 

 view is not accepted by authorities of such weight as Professor 

 Max Fiirbringer and Dr. Chalmers Mitchell. 



Two other types of doubtful ailRnity are commonly as- 

 sociated with the Galliformes. These are the Turnices and 

 the aberrant Opisthocomus of South America. The former are 

 small, Quail-like birds occurring throughout the warmer regions 

 of the Old World. Presenting characters in common with the 

 Galline birds, the Sand-grouse and the Rails, these birds should 

 perhaps be regarded as an offshoot from the Galliform stock, 

 though there is much to be said in favour of the contention 

 urged by Fiirbringer that these birds should be regarded as an 

 aberrant type of the Charadriiformes. 



As touching Opisthocomus, the Hoatzin of British Guiana, 

 the evidence is conflicting, as may be judged by the fact that 



