424 
Rev. H. B. Tristram on the 
on the centre of some of the feathers. But the most characteristic 
difference is in the coloration of the primaries and rectrices. 
The former are only faintly tipped with blackish brown; and on 
the tail, instead of a broad bar of black, there is a triangular 
mark, commencing on the inner edge of the external rectrices, 
and extending at its apex half an inch on the central quill. The 
tarsi, feet, and bill are of a dingy white. It is a very scarce bird, 
and only occurs on the southern limits of the Sahara, near 
Waregla, and in the southern portion of the Chamba territory. 
78. Alauda arvensis. (Skylark.) 
Stated by Capt. Loche to visit the Sahara in winter, but never 
came under my observation. 
79. Rhamphocoris clot-bey. (Cavaignac’s Lark.) Melano- 
corypha clot-bey , Bp. Consp. Av. p. 242. Ierapterhina cavaig - 
naciiy Des Murs, Rev. Zool. 1851, p. 25, pi. 1. 
This grotesque and singular-looking bird is found in small 
flocks on the mountain-sides south of El Aghouat. I never 
heard of its being obtained in any other locality, nor did I ever 
meet with it but on one occasion, when I obtained four speci¬ 
mens. In its flight it resembles the other Larks, and at first 
sight, from the broad black and white bands on the secondaries, 
might be taken for Certhilauda desertorum. It runs with great 
rapidity, and is very shy. The whole of the upper plumage is 
ruddy isabel. The neck and breast whitish, with large round 
black spots occupying the centre of each feather; cheeks and 
moustache black, with a white subauricular spot; throat white. 
Primaries brownish black; secondaries black, with the lower third 
part pure white; rectrices sandy white, with a small brownish- 
black spot on the inner web of the external feathers, increasing 
in each feather, until in the centre one it occupies a third of the 
whole length. Tarsi and feet covered with very prominent white 
scales; hind claw not equalling the length of the toe. But the 
most singular feature of the bird is its bill, which is, I believe, 
without an analogue. It is very solid, conical, and arched, 
“7 inch from the gape, and ’5 inch perpendicular diameter, stone 
colour, but black at the tip. The lower mandible has a sharply- 
cut notch on each side about the centre, over which a semicircular 
