294 On the Ornithology of Wilts. 



position of a bird's toes is not, as with men's fingers, stretched 



out and open, but the very reverse; it requires an effort in the I 



bird to spread open its toes, just as it does in a man to close his it 



fingers: hence, when it rises on the wing and flies through the in 



air, the foot is doubled up under the body, and the toes immediately ai 



contract, and only unbend again when about to seize the bough of i 



a tree : hence again, when it perches on a spray, the toes previously ni 



opened for the purpose, grasp it by their natural flexion, and i 



firmly clasp the support on which they have alighted. This is a m 



very excellent adaptation of peculiar structure to the required end, j k 



but in addition to this there is a most admirable piece of internal ri 



mechanism, which I cannot better describe than in the words of p< 



Bishop Stanley : — "^Connected with the thigh bones and leg, a set j i 



of muscles run down to the very extremity of the toes, so contrived \% 



and placed, that when, by pressure downwards, the limb bends, hi 



these fine muscles are pulled in, and therefore contract the toes, s 



thus making them grasp more firmly whatever the bird is resting | q 



upon; just as if a set of fine strings ran over pulleys to certain \\ 

 hooks, and were acted upon at the other end by a weight or pressure, 



and thereby made to draw in the hooks." Such, then, is the won- j ffi 



derful power given to perching birds, whereby they can hold \\ 



themselves securely even in sleep on so slender a support; this ^ 



faculty is shared in by the whole order; but as the families and H 



genera which compose this extensive division are so numerous, and ar 



obtain their food in such a variety of ways, it is clear that there , 

 must be considerable varieties in the development of their feet; the 



tribes which dwell among the boughs of trees, now hanging with u 



their heads downwards, now hurrying along the under side of the 0 f 

 branch, will require a foot somewhat differently formed from 



those which run on the ground, and perch on the topmost spray; ar 



still in so vast a nnmber, it will be impossible in the present paper ^ 



even to touch upon the points in which they vary ; but as through- ^ 



out the entire order there is so considerable a similarity of structure ! tj. 



in this particular, it will not be necessary for the due exposition t 



of my subject, to enter into further details upon it : we have said i \, 



enough to show how worthy is the construction of their feet to t j, 

 give a name to the whole order, as "Insessores," or Perchers. 



I 



