182 MR. W. K. PARKER ON THE OSTEOLOGY 



or the Syrrhaptes (PI. XXXVI. fig. 1), and less thick and clumsy than it is in the 

 Fowl-tribe (Pi. XXXVI. fig. 6). It is most like that of the Lapwing ; but its sphe- 

 noidal or middle facet is relatively larger, and the whole bone is broader, although it 

 has the same thin, sharp-edged character. Posteriorly the pterygoid articulates by a 

 double condyle with the os quadratum ; this articular surface is concave beneath, whilst 

 above, at the end of its upper process, the facet is slightly concave across and con- 

 vex vertically. This double articulation of the pterygoid with the os quadratum is 

 found also in the congeners of Hemipodius, viz. the " Gallinae," " Columbinse," and 

 " Pluvialina;." 



The OS quadratum (g.) is intermediate between that of the Pigeons (PI. XXXVI. fig. 6) 

 and Plovers (PI. XXXVII. fig. 1). The double upper articular head is perfectly normal, 

 and not single, as in the " Gallinaceae," where the homologue of the posterior crus of the 

 " incus "is aborted. The orbital process is intermediate in breadth between the Plover, 

 where it is broad, and the Pigeon, in which it is narrow — not so narrow, however, as in 

 the Fowls. There is no such process on the incus of Mammals. In the breadth of the 

 internal, convex articular surface for the lower jaw the os quadratum of the Hemipo- 

 dius is also halfway between that of the Plover and Pigeon, it being broader than in 

 the latter and narrower than in the former ; the external facet is similar in all three 

 (Pis. XXXIV. XXXV. & XXXVII.). The deep pit for the incurved end of the qua- 

 drato-jugal {qj.) is strictly pluvialine, this articulation being shallow and oblique in 



the Fowl-tribe and Pigeons. The lower jaw of Hemipodius ? is an almost exact 



counterpart of that of the Ptarmigan (Lagopus), being much stronger than that of the 

 Quail, Pigeon (PI. XXXVII. fig. 9), or Plover (PI. XXXVII. fig. 4). Perhaps the angle 

 at which the rami meet is a little more acute than in the Ptarmigan, and the angular 

 processes, especially the internal, are shorter and thicker relatively. The large mem- 

 branous space of the ramus is quite equal to what is found in Lagopus (PI. XXXVI. 

 fig. 9) ; in the Pigeon it is almost obsolete, and in the Lapwing small and oval. The 

 coronoid process of the surangular is very strong — as strong as in the Grouse. The 

 articular facets are also more like those of the " Tetraonidse " than those of the 

 Pigeons or Plovers. The dentary elements are short in Pigeons, longer in Plovers, 

 very long in the Tetraonidse (PI. XXXVI. fig. 9). The posterior part of the ramus in 

 Pigeons (the articulate, with its investing splints, the angulare, and surangulare) is very 

 thick and cellular — very difierent from the condition of this part in Lagopus, Hemi- 

 podius, and Vanellus. In the Syrrhaptes this part is intermediate between that of 

 Pigeons and Grouse. 



The " OS hyoides " has not been preserved in either of the skeletons oi Hemipodius 

 under inspection. 



In Hemipodius varius (PI. XXXV. fig. 5) I find nineteen vertebrae between the skull 

 and the sacrum (Professor O^en gives eighteen; see 'Cat.,' p. 274), and in the smaller 

 species there are twenty. In the latter kind the last sacral vertebra is (in this specimen) 



