40 ON THE CLASSIFICATION OF BIRDS. 
no less than by a variation of structure adapted to such 
habits. 
(42.) But before we proceed further, let us exhibit 
the divisions just intimated in a more definite manner, 
in the following table of the subfamilies : — 
Circles. Sylviab®, or Warblers. Subfamilies. 
^.Tupical. piHvc^^sJcnder, compressed; lateral jsvLviAN*. 
S. Sub-tT/pical. Bill and general structure more robust. PiiiLosiEi.ixji 
3 . Aberrant. 
■Bill depressed at its base ; legs length- 
ened; strong. 
Claws lengthened, and but slightly cur- 
■ ved ; live upon the ground. 
Saxicoiin®. 
Motacillin®. 
Bill strong, almost entire; hinder toe ■) 
and claw large. J 
As we shall subsequently touch upon the analogies 
resulting from this arrangement, we may at once pro- 
ceed to notice the several divisions in more detail. 
(4.S.) The Motaeillinte, or wagtails, form the most 
aberrant division of this group ; tliey are particularly 
interesting from their various and almost complicated 
relations. They are a small group of purely insectivo- 
rous birds, very well exemplified by the few species so 
common in this and most other countries of Europe. 
They live almost entirely upon the ground, where alone 
they seek their food, which consists entirely of insects : 
damp meadows, and the sides of standing or running 
waters, are the favourite haunts of these birds, and they 
run with such celerity, that, in this respect, as well as 
in their general black and white plumage, they can only 
he compared to the plovers. We consider them, in 
fact, as collectively representing the tenuirostral type of 
the perchers, or, what is the same, the grallatorial type 
among birds. The different wagtails of England are of 
tlie most typical genera {MotacUla and liudytes). These 
are succeeded by a beautiful little group pecuhar to India, 
named Enieurus {Jig. 128.), nearly all of which have 
a remarkably forked tail, and are clothed in a plumage 
of pure white, variegated with deep black : next to 
these conies the genus Anttius, or titlarks, slender- 
