68 CHAEADEIID^. 



forty genera, in addition to which twenty more generic names have been invented, raising 

 the whole number of generic names in this subfamily to sixty. These I propose to reduce 

 to six, which may be diagnosed as follows : — 



Key to the a. Outer tail-feathers an inch or more shorter than the central ones . . (Edicnemus. 

 enera. ^ Q en |- ra | tail-feathers never an inch longer than the outer ones. 



a 1 . Bill like that of a Bustard, with no nasal groove. 



a 



A hind toe ; tail more or less forked Glareola. 



b 2 . No hind toe ; tail nearly even Cursorius. 



b 1 . Nasal aperture placed in a conspicuous groove. 



c 2 . A lobe or wattle between the eye and the bill Lobivanellus. 



d 2 . No lobe on the side of the head. 



a 3 . Basal third or more of central tail-feathers white. With or 



without a spur on the wing Vanellus. 



¥. Little or no white at the base of the central tail-feathers. No 



spur on the wing Charadrius. 



Of these characters the only one respecting which the student is likely to have any 

 doubt is the presence or absence of a nasal groove. Fortunately this character appears 

 generally to be correlated with other differences in the shape of the bill. Wherever there 

 is a distinct nasal groove there is also a marked depression at or near the centre of the 

 outline of the culmen. The terminal half, more or less, of the profile of the culmen forms 

 an arch, called the vault of the culmen, and the basal half is a nearly straight line forming 

 an angle at its junction with the vault, and parallel to the chord of the arc. In those species 

 where there is no nasal groove there is usually no depression in the curve of the profile of 

 the culmen, which is convex throughout its whole length, the amount of curvature being 

 very small at the base, but very rapid at the apex. The difference in the shape of the two 

 kinds of bill is seen at a glance by comparing Plate X. with Plate XI. 



It is believed that these six genera are natural, or, in other words, represent relationship 

 or genetic affinity. So far as it is possible to know, each of these genera fulfils the con- 

 ditions of a true genus ; it contains no species which is not more closely related to some 

 other species within its limits than to any other species outside. Nevertheless it must be 

 admitted that the characters by which these genera are diagnosed are anything but satis- 

 factory. The rounded tail of CEdicnemus is reproduced in some species of Charadrius ; the 

 nasal groove appears to be in a transition state in (Edicnemus ; the fork of the tad almost 

 disappears in some species of Glareola ; the wattle on the face is very rudimentary in some 

 species of Lobivanellus ■ and the white bases of the central tail-feathers, which characterize 

 the genera Vanellus and Lobivanellus, appear in two species of Cursorius, C. bitorauatus 

 and C. clialcopterus, which are also aberrant in having a depression in the culmen. The 

 spur on the wing is only found in Vanellus and Lobivanellus, but is not present in all 

 the species of either genera ; and the hind toe, though always present in Glareola and 

 never in CEdicnemus or Cursorius, is of no generic value in the other three genera. 



