252 



BIRDS OF TUNISIA 



In my opinion a better definition of a subspecies would be the 

 following: A local race or form of a species which, while possessing 

 the decided specific characters of that species, differs from it in having 

 one or more of those characters modified to a certain extent, without, 

 however, being completely changed, or over-stepping the hard and fast 

 lines above alluded to. This modification may be one of coloration 

 and marking, or it may even be structural. It is presumably due to 

 local and natural causes, such as climate and environment, and is 

 probably brought about by a gradual process of development, varying 

 according to the greater or lesser divergence in the natural conditions 

 of the habitat of the particular form under consideration from those 

 of that where the species occurs in its typical form. 



Apologising for this digression, and returning to our subject, I 

 would say that the genus Galerida, owing to certain decided and well- 

 defined differential characters observable in its component members, 

 calls for subdivision into two distinct groups ; one including the 

 common Crested Lark of Europe, G. cristata (L.), and its allies, the 

 other, the small-billed Crested Lark of Southern Spain, G. tJieJihe, 

 (first distinguished by C. L. Brehm [Naum. 18.58, pp. 210-213]), and 

 its allies. The principal distinctive characters between the two 

 groups are the following : — 



G. cristata and allies. 



(1) Bill longer and finer. 



(2) Wing and tarsus shorter in 



proportion to the general size 

 of the body. 



(3) Bastard primary shorter or 



not longer than the primary 

 coverts. 



(4) Under wing-coverts rufescent. 



G. thcMa and allies. 



(1) Bill shorter and stouter. 



(2) Wing and tarsus longer in 



proportion to the general 

 size of the body. 



(3) Bastard primary longer or 



not shorter than the 

 primary coverts. 



(4) Under wing-coverts grey. 



Besides the above, there are other minor points of difference between 

 the two groups, both in their general coloration and marking, as well 

 as in their habits, but these are subject to more or less modification, 

 according to the particular districts inhabited by the various members 

 of the two groups. 



Owing to the varied nature of its territory and climate, which 

 naturally produces a corresponding diversity in its fauna and flora, 

 the Regency of Tunis is particularly rich in forms of Crested Larks, 

 both of the above-mentioned groups being well represented in the 

 country. Of each group forms occur there which are fairly separable 



