258 BIRDS OF TUNISIA 



The pale desert form of long-billed Crested Lark, which occurs 

 in Central and Southern Tunisia, appears to be referable to Canon 

 Tristram's Galerita arenicola {Ibis, 18.59, p. 68), agreeing with 

 the type, which is now in the Liverpool Museum. This specimen, 

 a male, obtained at Ehadma in Algeria on January 13th, 1857, is 

 rather a small example, but the species varies in size, and my Tunisian 

 collection contains both larger and smaller specimens than Canon 

 Tristram's type. In point of colour the plumage of G. c. arenicola 

 varies from a pale sandy-grey to a yellowish-isabelline, and birds of 

 both shades of colour are to be met with in the same district ; indeed, 

 it is by no means unusual to find the male and the female of a pair 

 somewhat different in colour. It must be noted, however, that this 

 difference in colour is more noticeable in living or freshly killed birds 

 than in dry skins. 



Until I met with such pairs, with the sexes differently coloured, 

 I felt inclined to distinguish the isabelline from the sandy-grey birds 

 and make two separate forms of them. This difference in coloration 

 between the sexes is noticeable also in some pairs of the small-billed 

 Crested Larks, as well as in some pairs of the Lesser Short-toed Lark 

 {Calandrella vmior), but it does not appear to be constant. 



G. c. arenicola is not at all uncommon in the Algerian Sahara, 

 and some of my finest and most isabelline specimens come from tbe 

 neighbourhood of Biskra and the plains to the east of that place, 

 where I found the bird abundant. 



From Marocco I have no specimens that can be referred to this 

 form, but it not improbably occurs in some of the inland districts 

 of the south of the Empire. 



In Tripoli G. c. arenicola appears to be wanting, at any rate Mr. 

 Dodson obtained no examples of it from that country, and, as 

 mentioned in the preceding article, he obtained but a single example 

 of G. c. macrorhyncha. This seems strange, considering the physical 

 character of that region, and its apparent similarity to the Algerian 

 and Tunisian Sahara, but there is no doubt some good reason for it, 

 at present unknown to us. 



The small-billed Crested Ijarks also, although occurring there, 

 appear to be less abundant in Tripoli than in Tunisia and Algeria, 

 their range, moreover, in the former country being restricted to certain 

 districts, and not widely extended, as in the two latter. On the other 

 hand, some of the other Larks, for instance the members of the 



