78 NEW YORK ZOOLOGICAL SOCIETY. 



some being made of calcareous tufa obtained in New York State, 

 and the effect of sea-worn rocks has been produced in some tanks 

 with other material. 



In the fresh-water tanks the problem has been somewhat more 

 difficult, but an attempt has been made to reproduce the stony 

 banks of streams with various kinds of rock. 



A supply of basalt from the gorge at Little Falls, N. J., has been 

 arranged in one of the larger tanks, in the exact position it occu- 

 pied on the edge of the stream. 



It is hoped, by the time this work is completed, that a series 

 of under-water pictures will be worked out in such a manner as 

 to greatly enhance the attractiveness of the exhibits at the Aqua- 

 rium. Seaweed will be introduced into the salt-water tanks, and 

 the fresh-water tanks will be decorated with fresh-water species 

 of plants. Aquatic vegetation of various colors growing on the 

 rock-work will also contribute largely to the interest of the ex- 

 hibits. This treatment is beneficial to the animal life contained 

 in them. The fishes appear to take an interest in exploring the 

 crannies in the rocks, while star-fishes, crabs, and other inverte- 

 brates cling to them constantly. 



A colony of ascidians is now propagating freely in one of the 

 salt-water tanks, the rocks being covered with hundreds of young 

 specimens. It will be possible to ascertain the rate of growth 

 of many invertebrate animals in this way. 



The observations already made tend to show that the species 

 exhibited retain their natural colors better than when the tanks 

 were lined with white tiles. After a few weeks the rock-work 

 acquires various rich tones, which are agreeable to the eye of the 

 visitor, and contribute to the comfort of the species exhibited. 



The accompanying photograph will serve to convey an idea of 

 the nature of the rock-work already in place. 



THE WORK OF THE COLLECTOR. 



In order that the local marine and fresh-water forms of life 

 might be constantly on exhibition, a collector was added to the 

 Aquarium force at the beginning of the year. The results se- 

 cured thereby have been very satisfactory. Collections of salt- 

 water fishes have been made constantly both in summer and in 

 winter, while numerous trips for fresh-water species have been 

 made to lakes and streams in the vicinity of New York. 



The collector has always been able to contribute an important 

 proportion of the minnows and other live food required for feed- 

 ing the collections, while the surplus marine life gathered along 



