290 Zoological N. Y. Zoological Society. [1; 16 



ently breaking up. Sometimes the speed is slow, but more often 

 it is rather rapid. Occasionally they indulge in a bit of racing 

 that makes high waves, the water surging up to the coping 

 of the pool. A porpoise speeding around the pool can make a 

 right-angled turn as quickly as a frightened fish, without lessen- 

 ing speed. 



When being fed all regularity of movement is abandoned, 

 and they rush in various directions to seize at the surface the 

 fishes slowly thrown into the pool. This continues for some 

 time after feeding, until all sunken scraps are gleaned from 

 the bottom. All food is swallowed under water. Frequently a 

 porpoise will play with a dead fish, thrusting its head clear 

 of the water and throwing the fish from five to ten feet away, 

 when it is recovered and thrown again. Such play may last half 

 an hour, or until the fish is reduced to scraps too small to be 

 thrown. It is not uncommon for two or three of them to be 

 engaged in throwing fishes at the same time and the practice 

 is becoming habitual. 



Several times a day they indulge in very active play, dart- 

 ing with mock ferocity after each other, or leaping quite clear 

 of the water and striking with heavy splashes. They often 

 swim on their backs, with the jaws out of water, or on their 

 sides repeatedly striking the surface with the head. When leap- 

 ing a favorite trick is to throw the body around until the dorsal 

 fin is forward, with a resulting splash that sends the spray 

 quite out on the floor. A high leap by one of them is usually 

 a signal that starts them all to leaping. Our fears that they 

 might leap quite out of the pool were unfounded ; they are 

 clever enough to avoid the wall which surrounds them. An- 

 other game is played by going around the pool with short dives, 

 each time striking the surface with the flat of the tail. When 

 the pool is entirely full of water their play is livelier than 

 when the water level is lowered. The increased depth gives 

 them more confidence and they often turn complete forward and 

 backward somersaults. The ordinary swimming motion of the 

 tail is up and down, but, if playfully charged by a companion, 

 the porpoise seems to make a spurt ahead by more or less side 

 action of the tail. This is not easy to determine, however, and 

 may be more apparent than real, as the water is too much dis- 



