BIRDS. 



59 



in which to build a ship in order to combine strength 

 with swiftness. 



Altliougli the body of Birds is covered with feathers, 

 these do not grow from the wliole surface, but are ar- 

 ranged in rows and patches, with bare spaces between. 

 Feathers are made up of a hard central portion or shaft, 

 and a vane, tlie latter being the broad portion which con- 



Fig. 103. — Skeleton of a Bird. 



A, head; nv, neck vertebrsB -, c, wrist; th, thumb; mc, metacarpus, or hand; ph^ 

 phalanges, or fingers ; r, radius ; u, ulna ; k, humerus ; sc, scapula, or shoulder-blade ; 

 erf, corocoid bone ; c/, clavicle, or " wish-bone " ; 5/, breast bone, or sternum ; /e, femur, 

 or thigh bone ; p,,pelyis ; ft, fibula and tibia united ; t, tibia, or leg j ts, tarsus, or in- 

 ■tep ^ ps, phalanges, or toes. 



sists of delicate plates that are united by minute barbs 

 along their edges, and thus made firm, — the plates not 

 separating from one another when pressed against the 

 air, as in flying. There are, however, downy feathers 



