Order XIII. PTEROCLETES. 



The Sand-Grouse, or Pigeon-Grouse as they were appropriately 

 called by Huxley, form a well-marked and distinct group that has 

 been referred by turns to the Colambce and to the Gallince ; but 

 since Huxley (P. Z. S. 1808, p. 302) showed how completely 

 intermediate between the two the Pteroclidce are, they have 

 generally been classed in a separate order. They are birds 

 ot: a yellowish-brown or buff colour as a rule, with somewhat the 

 build of Pigeons and even swifter flight, but with very different 

 bills and feet ; the bill, though of small size, resembling that of 

 the Gallince. The characters of the young are quite Galline. 

 Some are migratory, others resident. 



In the bill there is no soft base to the upper mandible. The 

 toes are generally four in number, but the hallux is small, and in 

 one genus wanting; all are on the same level; the anterior toes 

 are short and rather broad. Oil-gland present and nude. The 

 contour-feathers have aftershafts. The lateral bare tracts only 

 extend on the shoulders to the base of the neck, not on to it ; 

 the dorsal feather-tract has an interscapular fork. Primaries 11, 

 fifth secondary wanting. Tail-feathers 14 to 16. 



Palate schizognathous ; basipterygoid processes present. Cer- 

 vical vertebrae 15 or 16. There are usually two notches on each 

 side of the posterior margin of the sternum, but the inner notch 

 is sometimes reduced to a foramen ; keel of sternum very high. 



Deep plantar tendons Galline. Ambiens muscle present; other 

 muscles of thigh as in Columbce, Caeca present and large. Gall- 

 bladder present, and two carotids. 



Sand-Grouse live on hard seeds, and are, so far as is known, 

 monogamous. They lay three eggs on the ground, generally with- 

 out a vestige of nest. The eggs are peculiarly shaped, simply 

 oval, nearly a prolate spheroid, equally rounded at both ends, grey 

 or reddish grey and double-spotted. The young are covered with 

 down, richly marked, and they are able to run on. leaving the 

 egg- 



Family PTEROCLID^. 



Tarsus short and feathered. Wings long and pointed. The 

 family is found throughout Africa and in Western and Central 

 Asia, some forms migrating to parts of Southern Europe. Several 

 species occur in India, but none extend to the east of the Bay of 

 Bengal. 



Three genera are recognized, all occurring within the area to 

 which the present work is restricted. 



