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Show 314 DR. GADOW ON THE ANATOMY OF PTEROCLES. [Mar. 21, The general coloration of the Sand-Grouse is thoroughly protective, and is very distinctly marked throughout tbe genus by the dark crescent on the breast and the dark colour of the under surface of the wings. Though pronounced and apparently peculiar to the Sand-Grouse, a similar pattern is found in some of the Pigeons, as well as in the Plovers and in Grouse. The nestling plumage of'the Sand-Grouse consists of a thick downy cover with fine terminal hairs to each down-feather, much like that of the Plovers and Fowls, whilst the Pigeons, when hatched, are almost nude and are entirely devoid of downy feathers. The oil-gland is present and quite naked in Sand-Grouse and Pigeons (in some Pigeons wanting), whilst in the Gallinacei and Limicolse this organ is tufted. In both form and structure the " tarsus " and the claws of the Sand-Grouse closely resemble those of the Gallinacei, but are remarkable for the tendency to suppression of the first or hind toe, which in Syrrhaptes is entirely aborted. This never occurs amongst the Pigeons and Fowls, but is a common feature in the Pluvialine tribe. The bill and the nostrils of Pterocles are like the same parts in the Turnicidae, which, like Pterocles and the Columbae, are schizorhinal, whilst the Rasores proper are what Garrod termed holorhinal. OSTEOLOGY. As the osteology of Pterocles and Syrrhaptes has been fully described by Professors Parker and Garrod, it will be superfluous for me to do more than indicate some of the salient points. Prof. Parker says :- "There is no vomer in tbe Syrrhaptes to tie the two palatines together; and this is a sudden assumption of a columbaceous character." However, this is not of great importance, because most of the Tetra-onidse have also no vomer, or at least this bone is very much suppressed. The skull certainly bears many striking affinities to the Columba?. The Syrrhaptes keeps close to the Fowls in respect of its vertebral characters. Number of cervical vertebrae. Dorsal. Sacral. Caudal. Syrrhaptes 16 4 15 6 Pterocles arenarius. . 15 5 15 7 Columba livia 14 4 14 7 Gallus* 16 4 15 6 " There is much that is Pigeon-like in the pelvis of the Grouse and the Syrrhaptes." All the wing-bones, and in particular the humerus, strikingly resemble those of the Pigeons (see Garrod, P. Z. S. 1874, p. 255, fig. 1). M U S C U L A R SYSTEM. I myself have examined specially only the muscles of the pelvic region and those of the hinder extremity. As regards the * Parker, I. c. |