THE STUDENT'S AQUARIUM. 



19 



occupants of rivers, lakes and oceans leads me to the convic- 

 tion that there is not in this world greater gormandizers created 

 than the said occupants. Once in a while we read of the 

 devastations of the grasshopper and army worm on land, but 

 to use a phrase perhaps more expressive than polite, they do 

 once in a while " take a rest." Ask an oyster fisherman if he 

 ever knew a star fish to do so. I maintain that fish and the 

 lower orders of aquatic life will go through more and give up 

 their lives quicker than anything else created, for something to 

 eat. Perhaps you have seen the educated seal go up stairs, 

 ring a bell, bow, &c. Let me tell you, if you do not know it, 

 that he does it all for something to eat. No fish ! then no bell 

 ringing, bowing, &c. I knew of a pair of nest building Stickle- 

 backs who had been taught to ring a bell when they were 

 hungry. It came about by hanging a worm to a thread sus- 

 pended in the water : they used to pull on the thread when 

 there was no worm ; some one suggested a bell on the end out 

 of the water, and then the fish rang the bell because there was 

 no worm where the worm ought to be. 



Feed your fresh-water stock with worms and your salt- 

 water stock with any kind of clams : put in what you think 

 they will eat, and in an hour's time take out what is left. Al- 

 low nothing to decompose in the water, and all will be well. 



THE MARINE AQUARIUM. 



IN the management of a Marine Aquarium we support life 

 by air in the water, exactly as we do with fresh water, but 

 we encounter a difficulty here that we do not in fresh 

 water, — that is, Evaporation. Where you have only a small 

 body of water without a circulation, it is much more easily 



