. Culture methods for invertebrate animals;. Invertebrates -- Cultures and culture media; Invertebrates -- Collection and preservation. Marine A quaria 2 5 panying illustration. Strong circular currents are formed in the imme- diate vicinity of the cylinder, while at the far end the water moves very gently. There is also a noticeable upward motion from the bottom of the tank. The speed of rotation and the corresponding strength of currents may be regulated by the speed of the motor, controlled through a rheostat, and by means of a set of pulleys of different diameters. The dimensions of the cy
. Culture methods for invertebrate animals;. Invertebrates -- Cultures and culture media; Invertebrates -- Collection and preservation. Marine A quaria 2 5 panying illustration. Strong circular currents are formed in the imme- diate vicinity of the cylinder, while at the far end the water moves very gently. There is also a noticeable upward motion from the bottom of the tank. The speed of rotation and the corresponding strength of currents may be regulated by the speed of the motor, controlled through a rheostat, and by means of a set of pulleys of different diameters. The dimensions of the cylinder also affect the strength of the current produced and they therefore should vary according to the size of the aquarium used. The cylinder shown here is 4 inches in diameter and 6 inches long. About one inch is left above water. The tank is 25 x 15 x 14 inches. The bottom of the cylinder (B) is a celluloid disk. Non- corrosive material should also be used for the suspen- sion rod (C) and brace wires (W). The diameter of the pulley (P) is 12 inches. The water may be with- drawn from the tank through a siphon (S) the upper end of which is placed inside the revolving cylinder. When the cylinder is in rotation small organisms are never actually drawn against its wall, because the centrifugal force throws them away from it. They are then caught up in the circular currents and soon find themselves in quieter waters at the far end of the aquarium. In this manner the water in the tank may be changed without losing its inhabitants. When desirable, a constant flow of water may be supplied by placing the lower end of the overflow siphon (S) in a vessel (V), adjusted so that the top of it is level with the water in the aquarium. The water is introduced from a reservoir, in which it is kept at a constant level. If necessary the water from a laboratory faucet may be filtered through glass wool to remove sediment and other foreign matter. Imitation of tidal movement. The arrangement imit
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Keywords: ., bookcentury1900, bookcollectionameri, bookcollectionbiodiversity
