206 TJw New British Sand-Grouse. 



consist of numerous species, some or other of which are dis- 

 tributed over the whole of Africa and the hotter parts of Asia; 

 heat, as remarked by Swainson, being as essential to them as 

 cold is to the true grouse. Two species occur in Southern 

 Europe, Pterocles alchata and Pterocles arenarius, both of which 

 range into North Africa and Western Asia, but neither of which, 

 nor any other species of the family, has yet been known to visit 

 Britain — a noteworthy fact when viewed in connection with 

 these sudden inroads of a more distant species. A peculiar 

 style and arrangement of colour pervade the whole group. The 

 ground colour in all is a buffy or sandy hue. This is variegated 

 w r ith black, chesnut, and white or grey. The disposition of 

 these colours varies of course in each species, but they are dis- 

 posed in either more or less regular stripes or bands, or in 

 spots or blotches. Large and conspicuous masses of colour, 

 when they exist, occur on the under side of the birds. It will 

 thus be seen that the colours and their arrangement are such as 

 to make the birds as inconspicuous as possible in a sandy, arid 

 country, and greatly tending to their preservation from birds of 

 prey. 



The type and form of structure is peculiar, and in Pterocles 

 is pretty uniform. In size, the species vary from that of a wood 

 pigeon to a turtle dove. The beak is moderate and compressed ; 

 in some very slender ; the nostrils are placed near its base, and 

 partly closed by a membrane, which is covered above by feathers; 

 legs feathered in front to the foot ; toes short and moderately 

 robust ; the hind toe small and elevated ; tail more or less coni- 

 cal. In alchata the two middle tail feathers are lengthened into 

 filaments ; wings long, and the first two feathers the longest. 



In Syrrhaptes, the only other genus of the group yet dis- 

 covered, the beak is slender and diminutive. The first feather 

 of the wing and the two central feathers of the tail are pro- 

 longed into a slender filament, extending two or three inches 

 beyond the other feathers. 



The foot is densely clothed with short feathers down to the 

 claws, which are very broad and strong. The toes are united 

 together through their whole length, and covered beneath with 

 plates, which, when well worn, are nearly or quite hexagonal ; 

 when less worn projecting in a scale-like manner. The foot 

 thus forms a strong solid pad, well secured from injury from 

 the wearing particles of sand, or the sharp edges and rough 

 surfaces of rocks. No other bird with which we are acquainted 

 has the foot so solid and compact. 



Total length from tip of the beak to end of the central tail 

 feather, from 12 to 13 inches; length of wing from the carpal 

 joint to the end of the second wing feather, 8£ inches, the 

 filament of the first feather extending 3£ inches further ; tail, 



