THE PUBLIC AQUARIUM 265 



on the bank of a stream in New Jersey suggested the use of that 

 material in the New York Aquarium. 



After a few months' exposure to the water, artificial backgrounds 

 of rock acquire tones that are agreeable to the eye and help to secure 

 the effects sought. RockA^ork linings undoubtedly contribute to the 

 comfort of the animal forms kept in the tanks. Fishes take an in- 

 terest in exploring the crannies in the rocks, swimming through the 

 arches and resting under them, while crabs and other invertebrates 

 find good places to climb and cling. 



WOODEN EXHIBITION TANKS 



Glass-fronted exhibition tanks of moderate size sometimes are 

 made of wood with iron frames to hold the heavy plates of glass. In 

 the aquarium at Detroit the tanks are constructed of steel. Those on 

 the balcony of the New York Aquarium are built of 2-inch pine, 

 strongly bolted. These wooden tanks have been made durable and 

 sanitary by lining with cement laid on wire lath securely stapled to 

 the wood. The cement surface makes a good foundation for the 

 attachment of rockwork. They are 4 feet in vertical depth, with 

 outward sloping rear walls 3 feet back from the glass fronts, and 

 vary in length from 31/2 to 5 feet. Experience has shown that tanks 

 of such limited dimensions are not suitable for any fishes of active 

 habit even if of small size. A group of Chsetodons or other equally 

 lively small fishes turned loose in a big tank will outlive the same 

 number in a small tank. 



RESERVE TANKS 



Every aquarium needs some tanks to hold specimens not on exhibi- 

 tion and for other purposes. They are generally located along the 

 service passageway in the rear of the exhibition tanks. In the New 

 York Aquarium they are placed above the rear ends of the latter, 

 their overflows draining into them'. Reserve tanks, as they are called, 

 are about 3 feet in width and depth and vary from 6 to 8 feet in 

 length. The New York Aquarium has 26 tanks of this kind, most of 

 which are in constant use. They contain fishes for replacing losses 

 that may occur in exhibition tanks, injured fishes under treatment, 

 small fishes used as live food, and quantities of invertebrates used by 

 school-teachers for classroom study. 



FLOOR POOLS 



Floor pools are desirable for crocodilians, aquatic mammals and 

 birds, turtles, and fishes too large to be kept in glass-fronted tanks. 

 Seals, manatees, and porpoises do as well in them as any other lung 

 breathers subjected to indoor confinement. The larger such pools 

 can be constructed the better for their occupants. Seals and por- 

 poises need all the room for exercise they can get. Even when well 

 provided for in this respect, their endurance in captivity depends 

 upon the behavior of the individual animals. Those that are lively 

 and active may live for years, while the lazy and sleepy individuals 

 may not survive more than a few months. The New York Aquarium 



