COMPENSATION. 167 



struments for procuring food. The soft membranous sto- 

 mach, accompanies the hooked, notched beak ; the short, 

 muscular legs ; the strong, sharp, crooked talons : The car- 

 tilaginous stomach, attends that conformation of bill and 

 toes, which restrains the bird to the picking of seeds or 

 the cropping of plants. 



III. But to proceed with our compensations. A very 

 numerous and comprehensive tribe of terrestrial animals 

 are entirely without feet; yet locomotive; and, in a very 

 considerable degree, swift in their motion. How is the 

 i€ant of ftet compensated? It is done by the disposition 

 of the muscles and fibres of the trunk. In consequence of 

 the just collocation, and by means of the joint action of 

 longitudinal and annular fibres, that is to say, of strings 

 and rings, the body and train of reptiles* are capable of be- 

 ing reciprocally shortened and lengthened, drawn up and 

 stretched out. The result of this action is a progressive, 

 and, in some cases, a rapid movement of the whole body, 

 in any direction to which the will of the animal determines 

 it. The meanest creature is a collection of wonders. The 

 play of the rings in an earth-worm, as it crawls; the undu- 

 iatory motion propagated along the body ; the beards or 

 prickles, with which the annuli are armed, and which the 

 animal can either shut up close to its body, or let out to lay 

 hold of the roughnesses of the surface upon which it 

 creeps ; and, the power arising from all these, of changing 

 its place and position, afford, when compared with the 

 provisions for motion in other animals, proofs of new and 

 appropriate mechanism. Suppose that we had never seen 

 an animal move upon the ground without feet, and that the 

 problem was, muscular action, i. e. reciprocal contraction 

 and relaxation being given, to describe how such an animal 

 might be constructed, capable of voluntarily changing 

 place. Something, perhaps, like the organization of rep- 

 tiles, might have been hit upon by the ingenuity of an ar- 



* Contraction and expansion is the mode of progression in worms, 

 but not in reptiles ; in the class of serpents locomotion consists simply 

 of repeated horizontal undulations, viz. flexion and extension. Thus 

 the head being the fixed point, the body and tail assume several 

 curves ; the tail then becomes the fixed point, the curvatures are 

 straightened, and thus the animal advances with a serpentine motion. 

 By these successive curvatures and right lines alternating, it moves 

 forward at each step nearly the length of the whole body ; the ribs, 

 which Sir E. Home considers to act as feet, having nothing to do with 

 locomotion unless as affording a fulcrum for the muscles. 



Paxton. 



