POSITION OF THE JA^ANAS. 225 



decurved vomer is emarginate apically, as in certain Charadriidaj * (see 

 fig. 1). In the Ballidae it is, I believe, always sharp at the point. 



The maxillopalatine processes are rather slender and directed back- 

 wards; they have the form of concavo-convex lamellae, are not at all 

 swollen, and do not unite by some way in the middle line, 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 lachrymal 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 related 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 Parridae. 



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 (p. 226), pretty accurately, with hardly an exception, 

 with the chief groups of the Pluviales (the web-footed Laridae and Alcidae 

 being omitted as irrelevant to our present purpose) as determined by 

 other characters. In the Table + and - represent respectively the 

 presence or absence of the structure indicated. In the Plataleidae and 

 Gruidae 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 ( + ). 



The drawing (fig. 2, p. 227) of the sternum of Metopidius albinucTia will P. Z. S. 1881, 

 show how unlike it is to that of the Kallidse. In the latter group the p ' 645 ' 

 sternum is always peculiar in that the xiphoid processes exceed in length 

 the body of the sternum, which tapers to a point posteriorly, and from 

 which they are separated by very long and well-marked triangular notches. 

 The carina sterni also is less well developed ; and the clavicles are 

 weaker and straighter, being less convex forwards, than in the ParridaB. 

 The sternum and clavicles of Parr a and Metopidius in general form, on 

 the other hand, resemble closely the type found in some of the Pluvialine 

 birds (e. g. Thinocorus, Attagis). 



The pelvis, again, of the Bails presents certain well-marked pecu- 

 liarities. If that of Rallus aquaticus be taken as a typical form, it will 

 be found that the ilia are long and narrow, and but little expanded in 

 their preacetabular part. The postacetabular portion of the pelvis is 

 but little bent down on the preacetabular part ; and the ischia and pubes 



* Cf. Garrod, P. Z. S. 1877, p. 417, figf. 2-4. 



