BIRDS. 



59 



in which to build a ship in order to combine strength 

 with swiftness. 



Although the body of Birds is covered with feathers, 

 these do not grow from the whole 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, the latter being the broad portion which con- 



Fig. 103, Skeleton of a Bird. 



h, head ; nu, neck vertebrae ; c, wrist ; th< thumb 5 me, metacarpus, or hand ; ph, 

 phalanges, or fingers ; r, radius; w, ulna; A, humerus; sc, scapula, or shoulder-blade ; 

 e<f, corocoid bone ; c/, clavicle, or " wish-bone " ; st, breast bone, or sternum ; /c, femur, 

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

 step ; 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 



