6754 



Birds. 



In no position I could place the bird did the sole of the foot rest on 

 a flat surface, even conjointly with the heel-bone ; so that it cannot 

 be said to walk, but merely scuffles along with the assistance of the 

 wings, though it can thus make considerable way. I then put it to 

 the wall, but found it had no secure hold on the finished plastering of 

 the room. But on being placed on a roughened wall outside, it im- 

 mediately ran up with such surprising quickness that I was obliged 

 hastily to secure it. The tail was partially spread, so that the points 

 were even pressed against the wall ; but what chiefly surprised me 

 was that during its progress I could see the feet in action on each 

 side of the neck. On placing it against the wall with an object above 

 it, it remained in an attitude of perfect repose. The points of the tail 

 rested against the wall, as we should suppose ; but the feet were 

 hitched so far upwards as to be only about half an inch below the 

 bird's eyes ; the heel-bone I could see resting on the wall just below 

 the flexure, so that the femur, tibia and tarsus formed a single straight 

 line. It is obvious that from gravitation this straight line from the 

 foot to the head of the femur would always tend to the vertical, and 

 thus the ventral surface of the bird would be inconveniently pressed 

 against the surface clung to. But this is entirely prevented by the 

 salient nodosity at the heel, which intervenes and keeps the leg off, 

 forming also another point of support. The powerful but elastic 

 shafts of the tail lend additional aid. I found a recent bird could, 

 after death, be supported on the tail alone, provided it were prevented 

 from swaying over laterally. I unfortunately omitted to try whether 

 it could perch, but I thought of it immediately after I had killed it, 

 and, placing my finger in the claws, pressed them towards the breast. 

 The toes bent as usual, but the grasp was scarcely perceptible. I am 

 inclined to think they could not perch, at any rate without the volun- 

 tary action of the muscles ; they could not sleep on a branch in fact. 

 But if, before the limb become rigid, the leg is straightened and 

 stretched forward in the position when clinging, then the foot remains 

 perfectly pliable ; but a very violent flexure takes place between the 

 ultimate and penultimate phalanges of all four toes, so strong that 

 the points of the claws are doubled upon the sole, and cannot be 

 forced back so long as the leg is kept in this position, without the 

 exertion of far greater force than the bird's weight could bring to 

 bear. The hallux is lateral ; it will form a right angle with the inter- 

 mil fore toe with perfect ease, but cannot be brought completely for- 

 wards without manifest violence ; its most usual position with the 

 living bird is antagonistic with the external toe, and there seems 



