40 
SECOND BOOK 
3. “Why do you say this is the skeleton of a 
bony fish? Have not all fishes bones?” asked 
Arthur. 
“Not true bones,” replied Mr. Johnson. “A 
few kinds of fishes, such as the shark and the skate, 
have only gristle. 
4. “Let us now see how fishes differ from the rest 
of the backboned animals. You know what happens 
to a fish if you take it out of the water!” 
Skeleton of a Bony Fish. 
“ It very soon dies, of course,” said William. 
“Yes; it becomes suffocated just as surely as 
we should be if we were made to remain under 
water.” 
5. “That is because it has gills for breathing, and 
we have lungs,” said Arthur. 
“Of course! When we talked about the am- 
phibians I told you how it was that gill-breathing 
animals could obtain air from the water. Watch 
the gold-fish in this bowl, and you will see how 
they breathe.” 
