TUNISIAN CRESTED LARKS 251 



ON THE TUNISIAN CRESTED LARKS IN GENERAL. 



Before treating of the Tunisian Crested Larks in detail, I think it 

 advisable to make a few general remarks concerning the species and 

 subspecies, or forms, of the genus Galerida, Boie, to be noticed in this 

 work. 



I may also observe with regard to the generic name for the Crested 

 Larks, that in consequence of the name Galerita being preoccupied 

 in entomology. Dr. Madarasz, in 1899, proposed in its place that of 

 Ptiloconjs, and Mr. Dresser, in 1902, that of Corijdus. Boie's time- 

 honoured name, however, having a different, though no doubt an 

 incorrect, spelling, should perhaps be allowed to stand. 



As I have already had occasion to remark, when writing on 

 Tunisian birds in the Ibis, the Crested Larks are extremely 

 puzzling and difficult to deal with, owing to the large number of local 

 forms which occur, and to the fact that these forms intergrade, which 

 renders a satisfactory subdivision of them by no means an easy task. 

 Their separation is, indeed, more or less a matter of opinion, and in 

 making any such subdivision one has to be guided by one's own 

 judgment and discrimination. 



This brings one face to face with the vexed question as to what 

 constitutes a genus, what a species, and what a subspecies ? A satis- 

 factory answer to this question is not easy to give, and it would be out 

 of place to attempt to do so here. I may, however, briefly observe, 

 as regards the distinction between species and subspecies, that I 

 cannot agree with the opinion held by some zoologists of the present 

 day, that for the constitution of the former, strong or decided 

 characters are required, while for that of the latter slight or undecided 

 characters will suffice. This system makes the distinction between 

 species and subspecies merely one of degree, and offers no rule 

 whatever by which one may be guided. That strong and decided 

 characters are necessary for the constitution of a species is undoubt- 

 edly right, that is to say, characters which are clearly defined by hard 

 and fast lines, and which are, moreover, constant ; but surely it is not 

 right that we should be content with merely undecided characters for 

 the constitution of a subspecies. Such characters, although they may 

 be slight, should also be decided as far as they go, and constant within 

 the range of the particular form or subspecies under consideration. 



