182 BIFASCIATED LARK. 



Certhilauda closely allied to this, under tlie name C\ 

 Sahini. The sterna drawings of Avhich are given, are 

 certainly very diiFerent, even in important osteological cha- 

 racters. This bird is shorter by one-fifth of an inch, more 

 slender, and has a broader white band on the secondaries 

 than C. lifasciata. Mr. Tristram suggests, however, it 

 may be only a local race, althou-gh this idea is rather 

 negatived by the fact that both he and Captain Loche 

 had independently arrived at the conclusion, that these 

 were two species, and that the smaller one, though con- 

 fined to the southern and south-eastern districts, never 

 being found in the central or western, yet did not 

 supplant the common bird in the districts where it 

 occurred. 



These observations lead Mr. Tristram into a very in- 

 teresting discussion of the now exciting question of the 

 variation in species. Though tempting, I have not room 

 in this work to follow him in his remarks, but I must 

 refer the reader, to the first volume of the "Ibis," p. 

 429, et seq. 



I may remark, however, that while Mr. Tristram thinks 

 that observations he made on the Larks and Chats of 

 North Africa, illustrate the views of Mr. Darwin and 

 Mr. Wallace upon this subject, he distinctly repudiates 

 the possibility of such a law acting beyond the sphere of 

 species and race. "^I do not," he says, "for a moment 

 mean to imply that such birds as Rhamphoceris clot-hey 

 have been developed out of any known European form, 

 or that we are to presume so far to limit Creative 

 Power, as to endeavour to explain the growth of desert 

 species universally by the development of individual 

 peculiarities." 



It will be well for science and themselves, if all 

 naturalists will stop at the boundary line thus drawn 



