COLUHB-E 



are fused. Four ribs reach the sternum, of which the last 

 belongs, as in Pezopliaps only, to the first pelvic vertebra. 



The scapula and coracoid are, as in theRatites, 1 ankylosed, 

 and the angle between them approximates to that of the 

 Ratites in its wideness. 



The sternum has a fair keel, neither spina interna nor 

 externa, and the coracoids do not nearly meet. The clavicles 

 have no hypocleidium. 



I discuss the affinities of the Columbae under Pterocletes. 



PTEROCLETES 2 



Definition. -After-shaft small ; aquincubital. Oil gland nude. A crop 

 present. Cseca long. Muscle formula of leg, ABXY -f . Biceps 

 slip and expansor secundariorum present ; plantar tendons of 

 type IV. Skull schizognathous, holorhinal, with basipterygoid 

 processes. Both, carotids present. 



This group contains but two genera, Pterocles and Syr- 

 rhaptes, both of which are Old- World in range. Pterocles is 

 more widely spread than Syrrhaptes, extending southwards 

 to Africa and Madagascar. Syrrhaptes is confined to Central 

 Asia. These birds have a pigeon-like aspect, though NEWTON 

 has pointed out that Syrrhaptes has a plover-like flight. 



The feet are peculiar for the feathering, which extends to 

 the claws ; and in Syrrhaptes the three toes (the first is 

 altogether aborted) are encased in a common ' podotheca,' 

 which presents the appearance of ' a fingerless glove.' This 

 is not the case with Pterocles, which, moreover, has the first 

 toe. The sand grouse have a small aftershaft and a nude 

 oil gland. The rectrices vary in number from fourteen to 

 eighteen. Contrary to what is found in the pigeons the 

 newly hatched sand grouse is covered with down, and in the 



1 MOSELEY (' On the Structure and Arrangement of the Feathers in the Dodo,' 

 Reji. Brit. AKS. for 1884, p. 782) notes that the feathers are disposed in threes, 

 a feature which is, he says, apparent in pictures of the bird. 



2 M. BOGDANOW, ' Bemerkungen iiber die Gruppe der Pterocliclen,' Hull. Soc. 

 Imp. St. Pctersb. xxvii. 1881. p. 1(14; H. GAI>O\V, 'On some Points in the 

 Anatomy of Pterocles,' &c., P. Z. ,S. 1882, p. 312 ; D. G. ELLIOT, ' A Study of 

 the Pteroclidse, or Family of the Sand Grouse,' ibid. 1878, p. 233. 



