842 



ZOOLOGICAL SOCIETY BULLETIN. 



COMMON BROOK SUCKER. 

 A native fish that thrives well. 



study of local native fishes, the natural history 

 of which will be found no less interesting than 

 that of the exotic species. 



Aquatic insects afford a most intcrestinjj and 

 almost infinitely varied field for study, and tlieir 

 habits, metamorphoses, etc., may be most readily 

 investigated by this means. Again, if the 

 aquarist is interested in aquatic botany, he will 

 find here excellent opportunities and means for 

 studying many water ])lants. Marine life is 

 even more varied than that of the fresh water, 

 and endless opportunities are afforded to those 

 who live within reach of the sea. The micro- 

 scopist will also find a constantly changing and 

 ever interesting field of research in the minute 

 life of the aquarium. 



As an adjunct to the scientific laboratory, the 

 aquarium has become a necessity. Here it may 

 vary in size from the common finger-bowl for 

 minute animals to tanks for 

 the larger forms. The various - 

 aquatic laboratories such as 

 those at Wood's Hole. Massa- 

 chusetts, and at Naples i n 

 Italy, to cite two of the best 

 known, make constant use of 

 aquaria and could scarcely ex- 

 ist without them. Nearly all 

 colleges and universities have 

 some means of maintaining 

 aquaria, usually of the bal- 

 anced sort, while a few. such 

 as Trinity College, and Penn- 

 sylvania and Princeton Uni- 

 versities even possess facilities 

 for the storage and circula- 

 tion of sea water in larger 

 tanks. 



Naturally, larger aquaria 

 have the advantage of sup- 

 porting a larger and more va- 

 ried stock, but it should be 

 borne in mind that for scien- 

 tific as well as for other pur- 

 poses, the proper adjustment 

 is of far greater value than 

 mere space or variety of life. 

 In the high-school, grade- 

 school and even in the kinder- 

 garten, balanced aquaria have 

 found a place where they en- 

 courage nature study among 

 the children. The New York 

 Aquarium has equipped hun- 

 dreds of these for various 

 schools in New York City. 



THE MEANING OF BALANCE. 



The factors which govern life in the balanced 

 aquarium are the same as those which obtain 

 elsewhere in nature, with the important differ- 

 ence that certain of them are under control. In 

 fact we may consider the aquarium as a minia- 

 ture pond in which the conditions of food, tem- 

 perature and aeration are under the control of 

 the operator. In the natural pond the varia- 

 tions of temperature alone are sufficient to pro- 

 duce important cycles in the balance and in the 

 life of the organisms. 



To secure and maintain a balance in the in- 

 door aquarium is tlie most important problem 

 which confronts the amateur aquarist. Tem- 

 perature, which is such an important factor in 

 the natural pond, can easily be controlled in- 

 doors within the limits which are likely to af- 

 fect seriously the inhabitants of the aquarium. 





YOUNG MIRROR CARP. 



ery hardy and are excellent fishes for the beginne 



