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 COLEECTOR: 
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 
