PTEROCLETES 285 



Order PTEROCLETES. 



The order Pteroclctes contains but one family, PtevocUd;r, and the 

 distinguishing characteristics of the order and the family are there- 

 fore the same, and are dealt with under one head. 



Family PTEROCLID.E. 



The Sand-Grouse, or Pigeon-Grouse, as Huxley happily named 

 them, constitute an order of one family, which come half-way 

 between the Pigeons and Doves, Columhw, and the Gallinx or true 

 Game-Birds, to which latter they are very closely allied through the 

 real Grouse. In general external appearance they are, perhaps, 

 more nearly like the true Grouse than any other Game-Bird, but 

 they have also a strong resemblance to Pigeons in build, carriage of 

 head, etc., though l)oth feet and bill are Galline, 



In the Pigeons the toes are broad and well-fitted for perching, 

 whereas in the Sand-Grouse they are more fitted for ground-work, as 

 in the Galline birds ; the bill also has no cere, or soft skin over the 

 basal half, as it has in the Cohimbae. Both PterocUd.r and Cohimhn' 

 have eleven primaries and the fifth secondary wanting ; whereas the 

 Gallinx have only ten primaries, but possess a fifth secondary. In 

 all these orders the muscles of the thighs and legs are similar. The 

 fiexor perforans digltorum is attached to the flexor longus halhicis by 

 a fibrous vinculum, the former supplying the three front toes, and the 

 latter, as usual, the hallux, or hind-toe. The ambiens muscle is 

 present, except in a few Pigeons. The femoro-caudal, except in 

 Peafowl and Turkeys, the accessory femoro-caudal, the semi- 

 tendinosus and accessory semi-tendinosus are all present, as well as 

 both carotids, except in the Megapodes, 



