319 
CHAPTER XXXV. 
FISHES. 
FISH are, par excellence, the inhabitants of the ocean. They 
pass their whole existence in its waters; here they are born, here 
they live, and here they die; moreover, they are the most 
prominent of its occupants, they are larger, more numerous, and 
more varied than any other of the marine races. In the first 
chapter of our work, we stated that seven-tenths of the whole 
surface of the earth was covered by the seas. It is not surprising 
that one struck with the vast extent of the waters, exclaimed, 
“ Our globe has been made for the fishes !” 
The fish may be considered as the connecting link which joins 
the vertebrates and the invertebrates. Their organisation is more 
complicated than any of the animals we have as yet considered. 
Pliny enumerated ninety-four species of fish, Linnaeus increased 
the number to four hundred and seventy-eight, and now we reckon 
in the guild of the finny tribes, no less than 13,000 families, one- 
tenth of which confine themselves to the fresh waters. 
The fish are not scattered over the regions of the ocean without 
any order or regulation, but just as is the case with land animals, 
instinct teaches them to congregate in those localities best adapted 
for their existence ; the habits of many species are strongly defined, 
and sometimes the limits of their localities are very restricted, at 
other times a species is found extending over a large area. 
Unlike the land animals whose distribution is regulated by 
latitude, the fish are affected by the depth of the water; this is 
another consideration in the regulation of the distribution of species. 
Some live quite on the surface; others never quit the depths; and 
some pass their existence in the ooze and mud of the bottom. 
True salt-water fish dislike the fresh water of the rivers, and are 
therefore never found in estuaries; however, there are species which 
prefer an estuary life, and some, as the salmon, pass part of their 
