382 
VEKTEBRATA. 
TUE IGUAXODON. 
which hear the different colors ; these are more or less extended, according to the quantity of 
blood that reaches them, and the change of color is thus effected. 
There can be little doubt that this is a provision to enable this sluggish animal to approach its 
prey. "The more we search, into the habits and peculiarities of animals," says an eloquent 
writer, " the more are we led to admire the wisdom and goodness of the Creator. Tliroughout 
the animal creation, the adaptation of the color of the creature to its mode of living and place, 
of concealment, is highly remarkable, considered in reference to its preservation. If we look 
around, we shall discover that the colors of the smaller animals, and a umltitude of insects, con- 
tribute materially to their safety. Caterpillars wliich feed on leaves are generally either green, 
or have a large proportion of that hue in the colors of their coats. So long as it remains still, 
how ditRcult it is to distinguish the grasshopper from the leaf or spray on which it rests! The 
butterflies that flit among the flowers are decked in varied hues like them. The little birds that 
haunt the licdge-row^ side have feathers on their backs which harmonize with the color of the 
leaves, and feathers on their breasts which borrow the wdiite hue of heaven ; these render them 
less visible to the hawk above, or to the prowling cat beneath. The wanderer in the fields almost 
treads upon the skjdark before it rises, warbling merrily to Heaven's gate. The partridge can 
hardly be distinguished from the stubble amongst which it makes its nest ; and it is considered 
an accomplishment for the sportsman to be able to find the hare sitting. In northern countries, 
the winter dress of the hare and the ptarmigan is white like the snow. 
" If we turn to the waters, Ave shall find that it is nearly the same with its inhabitants. Frogs 
vary their color according to the nature of the mud or sand at the bottom of the ponds or streams 
they frequent ; nay, the tree-frog, Hyla viridis^ takes its name from the color which is so difficult 
to see among the leaves, where it adheres by the cupping-glass-like process at the end of its toes. 
The fish, especially those which inhabit fresh-water streams, are distinguished by the same pecu- 
liarities. Their backs are comparatively dark, like the water above them, and it requires some 
practice to discover them as they glide along the bottom of the clear brook in tliick dusky shoals. 
They come like shadows and so depart, under the gaze of the spectator. It is difficult to dis- 
tinguish the pike — " the ravenous luce," as old Tzaak Walton calls it — with its dark-green mottled 
back and sides, from the similarly-tinted leaves amid which that fresh-water shark lies on the 
