vir FLIGHT 209 
situated on or near the body, are able to spread the 
wings and regulate their utmost extremities. It is 
all-important that it should be so. All the, weighty 
organs must be accumulated in the body. To speak 
metaphorically, the wings must be made up of very 
little besides masts, sails, and cordage. 
The great "muscles that move the humerus I 
have already described ; they spring from the breast- 
bone and neighbouring bones. The muscles that 
bend or straighten the arm at the elbow arise from 
the top of the coracoid and from the anterior end of 
the shoulder-blade respectively. Nearly all their bulk 
and weight is near the body. One of them, the 
triceps, does a great work ; it straightens the elbow- 
joint, whereupon the hand is extended and the great 
ligaments get to work and spread the feathers, and 
then only small points remain for small muscles to 
see to. There are ten muscles springing from the 
further end of the humerus. These, of course, 
are not large, and most of them extend only to the 
wrist or metacarpal bone. Two of them, however, 
by the help of tendons move the fingers. Altogether, 
to do this work, there are five long muscles spring- 
ing either from the humerus or the ulna. And 
one of these attaches to the much-reduced thumb, 
called the bastard wing! There are also no less 
than eight very small muscles springing from the 
wrist and metacarpal bones, and filling up the space 
between the latter. All of these are attached to the 
fingers. or “thumb,” which, actually, engrosses no. 
1 See p. 42, where it is discussed what fingers in our hand 
correspond to the three in a bird’s wing. 
P 
