314 DR. GADOW ON"THE ANATOMY OF PTEROCLES. [Mar. '21, 



The ffeneral coloration of the Sand-Grouse is thoroughly protective, 

 and is very distinctly marked throughout the genus by the dark 

 crescent on the breast and the dark colour of the under surface of 

 the wings. Though pronounced and apparently peculiar to the 

 Sand-Grouse, a similar pattern is found in some of the Pigeons, as 

 well as in the Plovers and in Grouse. 



The nestling plumage of ih& Sand-Grouse consists of a thick downy 

 cover with fine terminal hairs to each down-feather, much like that 

 of the Plovers and Fowls, whilst the Pigeons, when hatched, are 

 almost nude and are entirely devoid of downy feathers. 



The oil-gland is present and quite naked in Sand-Grouse and 

 Pigeons (in some Pigeons wanting), whilst in the Gallinacei and 

 Limicolee this organ is tufted. 



In both form and structure the " tarsus " and the claws of the 

 Sand-Grouse closely resemble those of the Gallinacei, but are re- 

 markable for the tendency to suppression of the first or hind toe, 

 which in Syrrhaptes is entirely aborted. This never occurs amongst 

 the Pigeons and Fowls, but is a common feature in the Pluvialine 

 tribe. 



The bill and the nostrils of Pterocles are like the same parts in the 

 Turnicidse, which, like Pterocles and the Columbae, are schizorhinal, 

 whilst the Rasores proper are what Garrod termed holorhinal. 



Osteology. 



As the osteology of Pterocles andSi/rrhajites has been fully described 

 by Professors Parker and Garrod, it will be superfluous for me to do 

 more than indicate some of the salient points. Prof. Parker says : — 

 "There is no vomer in the Syrrhaptes to tie the two palatines together; 

 and this is a sudden assumption of a columbaceous character." 

 However, this is not of great importance, because most of the Tetra- 

 onidse have also no vomer, or at least this bone is very much 

 suppressed. 



The skull certainly bears many striking affinities to the Columbae. 

 The Syrrhaptes keeps close to the Fowls in respect of its vertebral 

 characters. 



Number of 

 cervical vertebrae. Dorsal. Sacral. Caudal. 



Syrrhaptes 16 4 15 6 



Pterocles arenarius. . 15 5 15 7 



Columba livia 14 4 14 7 



Gallus'' 16 4 15 6 



" There is much that is Pigeon-like in the pelvis of the Grouse 

 and the Syrrhajites." 



All the wing-bones, and in particular the humerus, strikingly 

 resemble those of the Pigeons (see Garrod, P. Z. S. 1874, p. 255, 

 fig. 1). 



Muscular System. 



I myself have examined specially only the muscles of the 

 pelvic region and those of the hinder extremity. As regards the 



* Parker, L c. 



