SAND-GROUSE. 235 



and allowed to run with barnyard fowls. They go in considerable flocks ; their nests 

 are large and rather clumsy affairs, built of sticks, leaves, and grass ; the eggs are white 

 and rather large ; and the birds themselves are much sought after for the table, as 

 their flesh is delicate and palatable, similar to that of the turkey. With this group 

 the list of the species properly considered as belonging to the order Gallinae ends. 

 The species, as will have been observed, are very numerous and of great variety, and 

 form one of the most if not, indeed, the most important group of birds in the 

 entire range of ornithology. 



ORDER XIII. PTEROCLETES. 



The sand-grouse, which form this order, have usually been included by naturalists 

 in the order Gallinae, but the obvious impropriety of this has at length been conceded, 

 and they are now elevated to a distinct order, lying between the Alectoromorphae on 

 the one hand and the Peristeromorphaa on the other. They resemble the first of these 

 great groups in their skull, palatines, maxillo-palatines, and bill ; and the second in 

 their pterygoid and basipterygoid processes, sternum, furcula, coracoid, and fore- 

 limbs. The feet, with its short hallux, entirely wanting in Syrrhaptes, and the short 

 tarso-metatarsus, are very unlike a pigeon's. The vocal organs are pigeon-like ; the 

 trachea is cartilaginous, with a pair of laryngeal muscles at its bifurcation ; but the 

 crop, gizzard, gall-bladder, and small intestines are like those of Gallinaceous birds. 

 The cceca coli are voluminous, and have twelve continuous longitudinal folds in their 

 mucous membrane. The pterylosis differs somewhat from that of the pigeon. The 

 lateral neck-spaces reach only to the beginning of the neck ; the superior wing-space 

 is absent ; the lumbar tracts coalesce with the posterior part of the dorsal tract, and 

 the latter joins the plumage of the tibia. The sand-grouse possess an after-shaft on 

 the contour feathers, thus differing from the pigeons, and, unlike the Gallinaceous 

 birds, have a naked oil-gland. In some characters these birds are plover-like, but they 

 drink like a pigeon, thrusting the bill up to the nostril into the watei', and retaining it 

 there until the thirst is satisfied. 



The family PTEROCLIDJS is composed of two genera, Pterocles and Syrrhaptes, the 

 species of which resemble each other in their general shape, having a rather heavy 

 body, long, pointed wings, and extremely short legs and toes. They are awkward 

 birds upon the ground, but move rapidly and gracefully on the wing. Pterocles has 

 the tarsi feathered in front, and in Syrrhaptes both tarsi and toes are completely 

 covered with feathers. In the osteology of these genera considerable differences are 

 observable. The skull of /Syrrhaptes is more pigeon-like than Pterocles ; the upper 

 frontal region is narrower between the eyes, and the ala? of the ethmoid are less 

 swollen between the crura of the nasal. In Pterocles the bones of the face are strong 

 like a pigeon's ; the lower jaw bends farther back ; the postorbital and squamosal 

 processes and the malar arch are also stronger. The scapula is grouse-like, and there 

 is one more caudal vertebra than in Syrrhaptes, and the styliform and sacral ribs 

 have no appendage, but both genera have a rudiment attached to the last haamapo- 

 - physis. The sternum of Pterocles has the episternum and hyosternal processes as in 

 Syrrhaptes ; but the external hypostemal processes are shorter. The species of sand- 

 grouse are inhabitants of Asia, India, and Africa, especially of the last continent, 

 where twelve of the sixteen or eighteen recognized species are found. Pterocles 

 comprises the great majority of known forms, Syrrhaptes having only two species. 



