338 



COMPARATIVE ZOOLOGY. 



United States. 



merous and varied in the whole class. It comprehends all 

 those tribes which live habitually among trees, excepting 



the llapacious and 

 Climbing Birds, and 

 whose toes three 

 in front, and one be- 

 hind are eminently 

 fitted for perching 

 only. The legs are 



Fio.324.-\Vhite-thi-oated Sparrow (Zonotrichia slender, and Seldom 



used for locomo- 

 tion. 



They are divisible 

 into two sections : 

 #. Clarnatores, with 

 nothing in common 

 but a harsh voice. In 

 most, the tarsus is 

 enveloped in a row 

 of plates, which meet 

 behind in a groove, 

 and the bill broad, 

 and bent down ab- 

 ruptly at the tip. 

 The typical repre- 

 sentatives are the 

 Tyrant Fly-catchers. 

 b. OscineSj or Song- 

 sters, all of whom 

 have a vocal appara- 

 tus, though all do 

 not sing. The an- 

 terior face of the 

 tarsus is one continuous plate, or divided transversely 

 into large scales ; and the plates on the sides meet be- 



Fio. 325. -Redstart (Seloj,haga rnticilla). Uuited 

 States. 



FIG. 326. White-eyed Vireo (rireo Noveboracensie). 

 United States. 



