240 THE OLD RED SANDSTONE. 
which inhabit our smaller streams; and no sooner does an 
individual succeed in expelling his weaker companions from 
some eighteen inches or two feet of territory, than straight 
way the exultation of conquest converts the faded and 
freckled olive of his back and sides into a glow of crimson 
and bright green. Nature furnishes him with a regal robe for 
the occasion. Immediately on his deposition, however, — 
and events of this kind are even more common under than 
out of the water,— his gay colors disappear, and he sinks 
into his original and native ugliness.* 
But of color, as I have said, though thus important, the 
ichthyologist can learn almost nothing from Geology. The 
perfect restoration of even a Cuvier are blank outlines. We 
just know by a wonderful accident that the Siberian ele- 
phant was red. A very few of the original tints still remain 
among the fossils of our north country Lias. The ammonite, 
* «In the Magazine of Natural History,’ says Captain Brown, in 
one of his notes to White's Selhorne, “* we have a curious account of 
the pugnacious propensities of these little animals. ‘ Having at vari- 
ous times,’ says a correspondent, ‘ kept these little fish during the spring 
and part of the summer months, and paid close attention to their habits. 
I am enabled from my own experience to vouch for the facts I am about 
to relate. I have frequently kept them in a deal tub, about three feet 
two inches wide, and about two feet deep. Whenthey are put in for 
some time, probably a day or two, they swim about in a shoal, apparent- 
ly exploring their new habitation. Suddenly one will take possession 
of the tub, or, as it will sometimes happen, the bottom, and will instant- 
ly commence an attack upon his companions; and if any of them 
venture to oppose his sway, a regular and most furious battle ensues. 
They swim round and round each other with the greatest rapidity, 
biting, (their mouths being well furnished with teeth,) and endeavor- 
ing to pierce each other with their lateral spines, which, on this occa- 
sion, are projected. I have witnessed a battle of this sort which lasied 
