26 



everything with which the water comes in contact — are 

 hard and soft rubber, wood, skite, glass, and brick, nothing 

 whatever of an injnrions character. Most of the loss of 

 salt water is supplied by water made sufiiciently salt by 

 the use of sea salt. As a result of the abundance of light 

 afforded, the slate backs and sides of the aquarium, and 

 the bare stones placed in them, are being gradually covered 

 with a dense growth of algfe developed directly from the 

 spores of algffi brought from the sea, just as it is seen de- 

 veloping on sea-walls and rocks, something, perhaps, alto- 

 gether unknown under the" usual unfavorable conditions. 

 The observations of the habits of fishes afforded by these 

 aquaria have been of great popular interest, while the 

 advantages of the observations to the general work of fish 

 culture in opening up new avenues for experiment in prac- 

 tical work may prove to be considerable. 



Some recent statements concerning the breeding haliits 

 of the common sunfish elicited the fact that the knowledge 

 of the subject is not j)Ositive. Referring to this. Prof. 

 Theodore N. Gill was led to say to the writer that "it is 

 a shame that we know so little of the habits of our com- 

 monest fishes." To which might be pertinently added, it 

 is a shame that the facilities afforded for observation of 

 fishes are so limited. 



It is to be hoped that a great aquarium may be developed 

 in connection with the work of the United States Fish 

 Commission, inasmuch as in addition to its practical use- 

 fulness to that organization, and its great popular interest, 

 the experience thei'e afforded will be of general public 

 benefit in jiffording a sure basis of practical knowledge 

 upon which the great cities of the country or institutions 

 of learning may draw when they decide to take up such 

 work. 



