BIRDS 171 
strength of this region (7.¢, where the legs unite with the 
body) is further secured by the fusion together of a number 
of the vertebre, which in the other vertebrate animals 
we have examined possess a certain freedom of move- 
ment. The hip-bones, moreover, extend much further 
forward than is the case in quadrupeds, and are firmly 
attached to the fused vertebrae. Like the wing, the leg 
also consists of three segments corresponding to the thigh, 
the shin, and the foot, in such an animal as the rabbit. 
The feet, whicharecovered 
with scales, end in four 
toes, three of which are in 
front, the fourth being 
directed backwards. This 
arrangement is common to 
all birds which perch, en- 
Upper arm bone 
Ulna 
Radlius 
Two Wrist __ 
abling a secure foothold 
to be obtained. The long 
Bones eee / jointed toes are armed 
getD iit 17 Dig with powerful blunt claws 
admirably suited _ for 
and Digi 7 scratching. Above the 
back toe is a short stout 
conical spur, 
The Tail. At the end 
of the tail a number of 
vertebre are fused  to- 
gether forming what is known as the ploughshare bone, 
which supports the long tail feathers, Above the end of 
the tail-region is a small rounded swelling, the oil-gland ; from 
this the bird obtains a supply of fluid, which it uses when 
preening its feathers. 
The Feathers. <A plucked Fowl will show that the 
feathers are confined to definite areas on the body. 
Fig. 110. - Fore-limb of flying bird, 
showing three main segments. 
1. Upper arm bone. 2. Lower arm bone, 
consisting of ulna and radius. 38. Wrist 
and hand, consisting of two wrist bones, 
bones of hand, and three digits. 
