182 
BIFASCIATED LARK. 
Certhilauda closely allied to this, under the name C. 
salvini. The sterna drawings of which are given, are 
certainly very different, 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. hifasciata. Mr. Tristram suggests, however, it 
may he only a local race, although 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 ‘This,” 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 Hhamplioceris clot-hey 
have been developed out of any knoAvn 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 
