32 PTEROCLID^. 



by the late Professor Garrod (P. Z. S. 1874, pp. 249-259), 

 that they must certainly be included in the same sub-order 

 with the Pigeons, although forming two quite independent 

 families. In arriving at that conclusion, it would, however, 

 appear that a little too much stress was laid upon the points 

 in which the Sand-grouse resemble the Pigeons and diifer 

 from the Fowls, without equal consideration having been 

 given to their afi&nities with the Tetraonidcs and with the 

 Plovers. Putting aside minor points, the principal features 

 may be briefly summed up as follows : — The nestling- 

 plumage of the Sand-grouse is a thick downy covering 

 like that of the Plovers and Fowls ; and, like them, 

 the young can shift for themselves, whereas the Pigeons 

 when hatched are almost nude, and quite helpless. The 

 suppression of the hind toe, characteristic of Syrrhaptes, 

 does not occur in Pigeons or Fowls, but it is a common 

 feature in Plovers. Unlike the majority of the Coliimhce, 

 the Pteroclidce possess a gall-bladder; and in the great 

 development of the cseca, they differ from the Columhidce, 

 and resemble the Gallince. Their mode of drinking is 

 entirely different from that of the Pigeons ; their flight 

 is rapid and Plover-like, without any of the gliding or 

 soaring motion characteristic of Pigeons ; their note is 

 certainly unlike a coo ; and, lastly, their eggs, although 

 elliptical in shape, are coloured, and are at least three in 

 number, like those of many Plovers, whereas with Pigeons 

 the eggs are two in number, and white. On the other hand, 

 the Sand-grouse resemble those genera of Pigeons which 

 possess an oil-gland, in having it naked : and not tufted as 

 in the Fowls and Plovers ; the skull and wing-bones are 

 Columbine, and in their myology also the Sand- grouse are 

 more nearly allied to the Pigeons than to any other group. 

 After much consideration the Editor thinks it advisable to 

 adopt for the Sand-grouse the separate Order to which Pro- 

 fessor Huxley gave the name of Pteroclomorpha* subse- 

 quently modified by Mr. P. L. Sclater to Pterodetes.-f 



No event in the annals of ornithology has excited more 

 * P. Z. S. 1868, p. 303. t Ibis, 1880, p. 407. 



