1428 



ZOOLOGICAL SOCIETY BULLETIN 



Photograph by C. Grant 



PORPOISES RACING UNDER THE BOW OF A STEAMSHIP 



In this photograph the porpoises are entirely under 



water, the female in advance having a baby 



porpoise swimming beside her. 



observed that the little fellow managed to mam- 

 tain the 'pace set by its parent. It is difficult 

 to make photographs of porpoises under such 

 conditions, because they keep just below the 

 surface, merely protruding the tops of their 

 heads to breathe. Their speed at such times is 

 of course equal to that of the vessel. 



Mr. J. K. Nye, of New Bedford, Mass., in- 

 forms me that he "timed" a school of porpoises 

 off the coast of South Carolina, when the vessel 

 was steaming at the rate of twelve miles an 

 hour. The porpoises remained with the vessel 

 about one hour. On another occasion when the 

 steamer was running at the rate of fifteen miles 

 per hour, a school of porpoises remained near 

 the bow for nearly two hours. 



I have seen a school of porpoises in the in- 

 land passage to Alaska, remain near the bow of 

 the United States Fisheries Steamer Albatross 

 for nearly three hours, while the vessel was 

 maintaining a speed of nine rniles an hour. This 

 happened at night, and as the sea was smooth 

 and phosphorescent, the movements of the rap- 

 idly swimming porpoises made a rarely beau- 

 tiful sight. 



Porpoises could no doubt swim much faster 

 than fifteen miles an hour, but would not be 

 likely to remain long with a ver}^ swiftly mov- 

 ing steamer. Careful observations made on 

 board some very fast steamers would furnish 

 interesting information on the speed attained bj^ 

 porpoises. Steamship passengers are always 

 interested in these lively animals, but not one 



Photograph by E. S. Greenlee 

 PORPOISES RACING UNDER THE BOW OF A STEAMSHIP 

 The porpoise at the left has a shark-sucker 

 {Removal attached on each side. 



person in a thousand, perhaps, thinks of ascer- 

 taining the actual speed of the vessel and the 

 length of time a school of porpoises may accom- 

 pany it. 



NOTES ON THE PERAl. 



Frovi the Ti'opical Research Station of the 

 Zoological Society. 



By G. Inness Hartley. 



THE perai, perhaps better known as the 

 piranha or cannibal fish, is one of those 

 mysterious inhabitants of the South x\mer- 

 ican fresh waters, of which very little appears 

 to be recorded. Like the barracuta of the Carib- 

 bean and other southern seas, wherever the 

 tropical rivers run fresh, it is an object of fear 

 to both men and beasts. Many gruesome tales 

 come to us of its depredations and savagery. 



The famity of the Characins, to which the 

 perai belongs, is verj^ large, and composes, ac- 

 cording to Eigenmann, more than one half the 

 fresh-water fishes of British Guiana. Though 

 usually smaller, the perai sometimes attains the 

 length of eighteen inches. It is flat and round- 

 ed, unlike most other ferocious fishes, and is 

 somewhat similar, at first glance, to our com- 

 mon porgy. Both the upper and lower jaws 

 of its not very large mouth bear a row of sharp- 

 pointed, razor-edged, triangular teeth, which, 

 like the teeth of a -shark, can shear cleanly 

 through soft flesh. They can nip off only a 



