62 



CLASS II. AVES. 



Hemarks. Animals of this class do not have 

 their lungs divided into lobes the whole being in 

 a single mass. Neither are their lungs ventilated 

 by their own contractions and dilatations. Air is 

 made to pass through them by the action of other 

 organs. It is admitted to the blood by an infinite 

 number of vessels from the axils of the wings and 

 various other parts of the body. 



Their forms are adapted to their peculiar cir- 

 cumstances ; they being the only animals of this 

 grand division which travel in the atmosphere. 

 The muscles of the breast are very large and 

 strong, giving great force to their wings. Their 

 covering of feathers, being non-conductors of elec- 

 tric fluid, secures them in some measure against 

 its frequent discharges in the form of lightning in 

 the upper regions ; and more especially w r hen sit- 

 ting upon their nests, on high trees. 



Their rapid passage through different regions 

 of the air, and its perpetual action upon them, af- 

 ford them the means of prognosticating the varia- 

 tions of the atmosphere by a method totally un- 

 known to us. 



THE CLASS AYES is DIVIDED INTO six ORDERS* 

 ORDER I. ACCIPITRES. .^,/^- 



y 



Having strong hooked beaks and claws ; toes 

 4 ; the thumb toe, and inner one of the other three? 

 are larger. Birds of prey. 



VULTUR, (vulture,) bill straight, hooked at the 

 tip, and covered at the base by a cere or skin : 



