INTRODUCTION. 9 



number of feathers, bearing some resemblance to the quills 

 of the true wing. They grow from a little bone, which is 

 united to the third or wrist joint of the wing ; and they and 

 the bones by which they are supported, are generally strong, 

 in proportion to the power of flight in the bird. Indeed, 

 there is generally a development of all that part of the wing 

 which corresponds to the hand, proportional to the power of 

 flying. Thus, in the wing of the jer-falcon, which may be 

 considered as being the bird of finest and most graceful 

 flight, the thumb consists of two distinct bones, and even a 

 marking as if the last were two united ; and the four fingers 

 may be traced, the first in a long bone, the second in a small 

 one, and the third and fourth in two ribs united by a very 

 thin plate of bone. The use of the bastard wing is not very 

 well known, because the action of the different parts of the 

 wing, during flight, is not easily observed ; but it is probable 

 that it prevents the wing from turning upwards, and even 

 gives the point of it a downward motion, in the contrary 

 direction to that in which the whole wing is moved, and thus 

 propels it forwards. 



4. The lesser wing-coverts. These are the first parts of the 

 plumage of the wings which, in all birds, take the form of 

 definite and firm feathers. There are generally several rows 

 of them ; and there are under-coverts, which answer to them, 

 and line the under or inner sides of the wings, but these are 

 more slender and downy in their consistence, and, generally 

 speaking, they have less colour. 



5. The greater wing-coverts. These lie under the lesser 

 ones, and are still larger and stronger, stretching a consider- 

 able way over the quills or flying feathers, and being supports 

 to these for a greater part of their length than the lesser 

 coverts. They are also much stronger in proportion to the 

 coverts which answer to them on the under sides of the 

 wings. 



