COMPENSATION. 
165 
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 
want of feet 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- 
latory 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 roughness of the surface upon which it creeps; 
and the power arising from all these, of changing its place 
and position, affords, 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 prpblem 
was; muscular action, i. e. reciprocal contraction and rel¬ 
axation being given, to describe how such an animal might 
be constructed, capable of voluntarily changing place. 
Something, perhaps, like the organization of reptiles, 
might have been hit upon by the ingenuity of an artist; or 
might have been exhibited in an automaton, by the com¬ 
bination of springs, spiral wires, and ringlets; but to the 
solution of the problem would not be denied, surely, the 
* Contraction and expansion is the mode of progression in ivortns, but 
not in reptiles; in the class of serpents locomotion consists simply of re¬ 
peated horizontal undulations, viz. flexion and extension. Thus the head 
being the fixed point, the body and tail assume several curves; the tail 
thtu becomes the fixed point, the curvatures are straightened, and thus the 
animal advances with a serpentine motion. By these successive curva¬ 
tures 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. 
