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 efibrt in the 

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

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

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

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

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

 opened for the pxirpose, grasp it by their natural flexion, and 

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

 very excellent adaptation of peculiar structure to the required end, 

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

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

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

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

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

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

 thus making them grasp more firmly whatever the bird is resting 

 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- 

 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 

 genera which compose this extensive division are so numerous, and 

 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 

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

 branch, will require a foot somewhat differently formed from 

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

 still in so vast a number, 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 

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

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

 enough to show how worthy is the construction of their feet to 

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



