Order GALLIFORMES. 



Family PTEROCLID^ or SAND GROUSE. 



The Sand Grouse are a remarkably isolated group of birds, many 

 of their affinities being with the Game Birds, whilst others, 

 especially those of an osteological character, are with the Pigeons. 

 Some systematists, as, for instance, Sclater and Stjeneger, elevate 

 them to the rank of a separate order ; others, as Reichenow and 

 Fiirbringer, regard their characters of only sufficient importance 

 to rank as a sub-order. Some naturalists include them in the 

 great natural order of the Columbiformes ; others, with as much 

 propriety, include them with the equally distinctive group of 

 Galliformes. The Sand Grouse are one of the few ancient sur- 

 viving links in the now broken chain of Avian descent ; and it 

 is impossible, in the state of our present knowledge, to say to 

 which existing group of birds they are most closely allied. Their 

 double-spotted egg (having underlying as well as surface 

 markings) and precocious nestling is the casting vote in favour 

 of placing them with the Galliformes. Their sternum contains 

 two notches on each side of the posterior margin. In the 

 modification of their cranial bones they are schizognathous ; 

 nasals schizorhinal ; oil-gland nudej hallux small and some- 

 times absent ; moult single, in autumn. Young hatched covered 

 with down, and able to run almost at once. 



The number of species and their distribution are the same as 

 those of the genus. 



