522 THE SOCIAL LIFE OF THE LOWER ANIMALS. 
The bill of fare of fossil animals, though written in characters ' 
less clear and less complete, can, however, still often be read in — 
their coprolites. We should not despair even of discovering some — 
day the fishes and the crustacea which were devoured by the plesi- 
osaurs and the ichthyosaurs, and of finding that some parasitic — 
worms may have been introduced with them into their spiral 
cee 
m. 
Naturalists have not always studied with sufficient care the 
relations which exist between the animal and its food, though 
these relations would furnish the observer with information of i 
high importance. a 
Every organic body, conferva or moss, insect or mammal, 
becomes the prey of some beast; liquid or solid, sap or 
horn or feather, flesh or bone, all disappear under the teeth 
one or the other; and to the remains found in each correspond 
the instruments necessary for their assimilation. These primii T 
relations between animals and their diet maintain the industry of 
each species. 
We find on taking a nearer view, more analogy between ' 
animal world and human society, and, without seeking farther, 
can say there is no social position which has not its count 
among the animals. er 
The greater number of them live quietly on the fruits of 
labor, and practise a trade which supports them ; but aside 9 
lish themselves, some as parasites in the thickness of ther 
the others as commensals by the side of their host. 
It is some years since one of our learned and inte 
fréres of the University of Utrecht, Professor Harting 
charming little book on the industry of animals. He es ji 
our attention to the fact that most of the trades are P™ 
ee 
miners, masons, carpenters, paper-makers, weavers, 
even say lace-makers, who work at first for themselves’ ; 
wards for their offspring. Then there are some WS S 
soil, strengthen arches, clear up useless pieces of es 
miners consolidate works ;* others build huts oF P 
EET EE 
the 
* The Mygales among spiders, the Andrena, the mole-eris o 
Arenicolæ, Terebrellæ, Sabellæ, Tubifex, etc., among the worms. 
