INSTRUCTION. 7 
can always teach another something, the writer feels 
impelled to mingle a little instruction in closes to suit 
the weakest stomach, that those who have not skipped 
this chapter on account of its title, may at least receive 
something for their perseverance. They need not sup- 
pose for a moment that the writer pretends to insist upon 
what he shall write as infallible, but where his readers 
difier from him, is perfectly willing to admit that he is 
entirely mistaken ; the buyer of a book is always right, 
the author a toiijours tort. 
He supposes — let there be no misnnderstandings when 
he accidentally uses a stronger word — that fishes are 
divided into two great orders, and are distinguished as 
having bony or cartilaginous skeletons ; thns a quawl, 
provided he be a fish at all, would be a very cartilagi- 
nous one, and a catfish with his back fin erected, as the 
writer has often learned to his cost, is a bony fish. 
As the cartilaginous fish are of small account, the 
reader may forget all about them if he wishes, but he is 
recpested to remember the useful division of those hav- 
ing bony skeletons into the great classes, easily distin- 
guished, of the soft finned and spiny finned, called in 
foreign languages by the horrible terms ^nalacojpterygii 
and acanthopterygii — terms unpronounceable except by a 
Dutchman or a philosopher. These classes are distin- 
guished, as the English words imply, by their having the 
rays of their fins soft and flexible or hard and spine-like. 
The investigator may determine their peculiarities by 
pressing strongly upon the points of the fin rays ; if 
nature intimates that his organism is suffering, the fish is 
a acanthop^ etc. ; if not, why not. 
