ZOOLOGICAL SOCIETY BULLETIN. 



845 



nearly as long as the diameter of the vessel. 

 The fish continued to live in good condition for 

 several weeks until the experiment was acci- 

 dentally brought to an abrupt end. 



On no account should the ordinary globes be 

 used. Thej r are often sold because of their 

 cheapness, but they give the specimens a very 

 badlv distorted appearance, and what is much 

 worse the constricted top affords but a small sur- 

 face area for exchange of gases with the air and 

 makes it almost impossible to clean the jar prop- 

 erly. The slight additional cost in securing the 

 proper sort of tank will be repaid many times 

 in the satisfaction with which it may be man- 

 aged. 



PLACING THE AQUARIUM. 



The aquarium jar or tank should be placed 

 on a firm base where it will not be subjected to 

 much vibration and where it will not have to be 

 moved frequently. Fishes are sensitive to vibra- 

 tion in the water and jarring or moving the 

 aquarium frightens and disturbs the inhabit- 

 ants. It should not be placed too near a radia- 

 tor, and if it is near a window it should be care- 

 fully guarded from draughts in cold weather. 

 North windows are the most suitable, since suf- 

 ficient light is afforded for the growth of the 

 plants and the direct rays of the sun, which 

 tend to heat up the water and to over-stimulate 

 the plant growth, will be avoided. If a south 

 exposure is necessary, the tank may be placed 

 farther from the window or it may be shaded 

 from the strong sunlight by a small screen of 

 cheesecloth stretched upon a light frame. 



PLANTING THE AQUARIUM. 



This is an important proceeding, as upon the 

 successful establishment of the plant growth 

 depends the aeration of the standing aquarium 

 and consequently the health of the animals. 

 Many kinds of aquatic plants, both wild and 

 cultivated, will grow readily in the narrow limits 

 of the aquarium. The best species are those 

 that will live entirly submerged and which have 

 (1) narrow, ribbon-like or (2) finely divided 

 leaves. 



In the first class are the tape-grass (Fallis- 

 nerid), arrow-head (Sagittaria) and pond-weed 

 (Potamogeton) ; and of the second class, fan- 

 wort (Cahomba), milfoil (Myriophyllum) , 

 hornwort (Ceratophyllum) and waterweed 

 (Anacharis). Two or three of these plants 

 placed together in the tank give a little diversity 

 and make it more attractive than will a single 

 species. Fine gravel or coarse sand or a mix- 

 ture of these should be placed in the bottom of 

 the aquarium to the depth of one or two inches, 

 depending upon the size of the aquarium. 



The plants can be anchored by packing their 

 roots in the sand or gravel, and if necessary 

 large pebbles can be placed about the bases of 

 the plants until they become firmly rooted, or 

 the lower ends of the stems may be weighted 

 by wrapping with a small piece of soft lead just 

 above the roots. Some aquarists insist that a 

 layer of soil should first be placed under the 

 gravel, but in completely aquatic plants this is 

 quite unnecessary, while the soil is often a 

 source of danger to the animal life through the 

 decomposition of its organic ingredients. 



Nearly all of these plants will slip readily and 

 the slips will soon form their own roots if an- 

 chored to the bottom by a pebble or a strip of 

 lead. The tape-grass sends out runners, from 

 the joints of which young shoots arise. 



To obtain the best results, the aquarium 

 should be planted at least a few days before the 

 animals are introduced. This allows the plants 

 a better opportunity^ for taking hold of the 

 sand and it also permits them to thoroughly 

 aerate the water in preparation for the animal 

 life. 



The plants must of course be provided with 



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MOSQUITO LARVAE: ALL GLASS AQUARIUM. 

 This rectangular type of jar can be had in all the smaller sizes 

 and is the best form of the all glass jar. For balanced 

 aquaria, the height should not exceed the width. 



