224 ON THE ANATOMY AND SYSTEMATIC 



metacarpal extensor, as in many other groups of birds. There is also a 

 thin fibrous expansion given off just before this to the teudon of the 

 tensor patagii longus, and the tissue of the patagium generally, as in 

 many Pluvialine birds *. This splitting up of the tensor patagii brevis 

 tendon into two distinct slips, the external one in turn giving off a 

 special wristward slip, occurs in many Pluvialine birds (e. g. in Namenius 

 arquatus, Totanus calidris, Machetes pugnax, Himantopus nigi-icollis, 

 ThinocoruSj Attagis), but never in the Bails, where the tendon is always 

 much more simple, not being divided into two separate parts, or giving 

 off a wristward slip. In fact, in most Eallidae it runs quite simply, as 

 a narrow straight tendon, on to the origin of the extensor metacarpi 

 muscle, and there stops. 



The trachea is provided with the usual pair of sterno-tracheal muscles ; 

 and the lower larynx, which is of simple structure, has also only a single 

 pair of intrinsic muscles. 



Osteology. 



From a consideration of the pterylographic, visceral, and myological 



features only of the Parridae, perhaps no very definite conclusion as to 



their affinities could be drawn. But their osteological characters, in this 



case, leave no doubt as to their real position. All the skulls of ParridsD 



which I have examined, including those of Parrce jacana a,nd.gymnostoma, 



Metopidii indicus, africanus and albinucha, and HydropJiasianus chirurgus, 



like that of Hydralector cristata figured by Grarrodt. are strongly 



schizorhinal, therein differing completely from that of the Bails, and 



P. Z. S. 1881 resembling that of the Pigeons, Plovers, and their allies (the " Cha- 



p. 643. radriiformes " of Garrod ) only amongst Homalogonatous birds. 



Fig. 1. 



Skull of Parra jacana, from below; natural size. 



There are well-developed basipterygoid processes, which are always 

 absent in the Eails, though of very frequent occurrence amongst the 

 " Pluviales," occurring in all the Charadriinso and Scolopacinae I have 

 examined. 



In Parra jacana and Metopidius albinucJia, the long, narrow, slightly 



* In Hydrophasianus much the same arrangement of the tensor patagii brevis obtains, 

 to judge from a small drawing in Garrod's MS. 



t P. Z. S. 1873, p. 34, fig. 5. \ P. Z. S. 1874, p. 117. 



