164 



VERTEBEATA: AVES OR BIRDS. 



in front, separated from the rest of the tarsal covering by 



a groove. 



The Ravens are the largest of the Corvidse, being about 

 two feet long, and readily distinguished from the Crows, 

 not only by their larger size, but by the feathers of the 

 throat, which are long, acute, and separated ; while the 

 feathers on the throat of the Crows are oval in shape and 

 closely blended. 



FIG. 192. 



Magpie, Pica hudsonica, Bonap. 



The Magpies (Pica) have the bill much curved, and the 

 tail exceedingly long, making the total length of the bird 

 about h'fteen or twenty inches (Fig. 192). 



