FISHES. 
41 
6. “ They keep on opening and shutting their 
mouths,” said Arthur. 
Bowl of Gold-fish. 
“ Just as if they were gulping the water in,” 
added his brother. 
7 . “ That is just what they are doing,” said Mr. 
Johnson. “But you 
must not think they are 
drinking it. They send 
it out again through the 
gill-slits, which you may 
see regularly opening for 
that purpose. 
8. “ Here is a dead fish 
that has been brought to 
me from the market. Let us examine its gills. 
First, I lift up the gill cover, which fits over the 
Gill of Fish. 
