1881.] ANATOMY OF THE JAfANAS. 643 



Pigeons, Plovers, and their allies (the " Charadrii formes" of Garrod ') 

 only amongst Homalogonatous birds. 



There are well-developed basipterygoid processes, which are always 

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

 " Pluviales," occurring in all the Charadriinae and Scolopacinse I 

 have examined. 



In Pa7-ra jacana and Metopidius albinucha, the long, narrow, 

 slightly decurved vomer is emarginate apically, as in certain Cha- 



SkuU of Parra jacana, from below ; natural size. 



radriidse^ (see fig. 1). lu the Rallidse it is, I believe, always sharp 

 at the point. 



The maxillo-palatine processes are rather slender and directed 

 backwards ; they have the form of concavo-convex lamellae, are not 

 at all swollen, and do not unite by some way in the middle Hue, the 

 vomer appearing between and (when the skull is viewed from the 

 palatal aspect) below them. 



There is no ossified internasal septum, nor any ossification of the 

 narial cartilages. The lacrymal is small, ankylosed with the naso- 

 frontal region of the skull above, and with the " pars plana " below. 



On the posterior aspect of the skull there are no traces of the 

 occipital fontanelles, which are found in so many of the birds re- 

 lated to the Plovers. 



The supraorbital impressions for the nasal glands, which are so 

 conspicuous in most Plovers, the Gulls, Auks, and many other birds, 

 are absent in the Parridse. 



The combinations depending on the presence or absence of basi- 

 pterygoid processes, of occipital foramina, and of impressions on the 

 top of the skull for the supraorbital glands, coincide, as may be seen 

 from the following table, pretty accurately, with hardly an excep- 

 tion, with the chief groups of the Pluviales (the web-footed Laridae 

 and Alcidse being omitted as irrelevant to our present purpose) as 

 determined by other characters. In the Table -f and — represent 

 respectively the presence or absence of the structure indicated. In 

 the Plataleidse and Gruidse the nasal glands occupy the truncated 

 edge of the cranium above the orbits, and hardly appear on its upper 

 surface : this condition I have indicated by the use of the double 

 sign (±). 



I P.Z.S. 1874, p. 117. 



^ Cf. Garrod, P. Z. S. 1877, p. 417, figs. 2-A. 



