THE PICKED DOG-FISH. 203 



good idea of the powers of this tremendous weapon when wielded by the iron muscles of 

 the Thresher : 



"One morning during a calm, when near the Hebrides, all hands were called up at 

 three A. M. to witness a battle between several of the fish called Threshers or Fox Sharks and 

 some swordfish on the one side and an enormous whale on the other. It was in the middle of 

 summer, and the weather being clear and the fish close to the vessel, we had a fine opportunity 

 of witnessing the contest. As soon as the whale's back appeared above the water, the 

 Threshers, springing several yards into the air, descended with great violence upon the object 

 of their rancor, and inflicted upon him the most severe slaps with their long tails, the sounds 

 of which resembled the reports of muskets fired at a distance. 



' ' The swordfish in their turn attacked the distressed whale, striking from below, and thus 

 beset on all sides, and wounded, where the poor creature appeared, the water around him was 

 dyed with blood. In this manner they continued tormenting and wounding him for many 

 hours, until we lost sight of him, and I have no doubt that they in the end completed his 

 destruction." This strange alliance of two different fish against a marine mammal is a truly 

 curious circumstance, and may have a deeper meaning than appears on the surface. 



The food of the Thresher consists mostly of fish, and in the stomach of one of these 

 creatures taken off the coast of Cornwall were found a quantity of young herrings. The color 

 of the Thresher is dark slaty-blue above, and the same color, but mottled with white, below. 



It abounds in all warm seas, and in summer is one of the most abimdant kinds on our 

 New England coast. It is also occasionally taken on the Pacific coast. The Thresher is 

 the only representative of its family. 



THE family of Sand Sharks includes one genus and three species, of which Carcharias 

 americanus is the more familiar form. It is a small voracious Shark, rather common on our 

 Atlantic shores. 



The family of Porbeagles is well known through its very familiar representative, the 

 Mackerel Shark (Isurus glaucus). 



A species, allied of the genus Lamna, was lately discovered at Wood's Holl, Mass. It is 

 a large and fierce creature. 



A large spotted species of the Whale-shark family inhabits the California waters. 



The family which embraces the Port Jackson Sharks is represented in California seas by 

 Cestracion francesci. 



Another family in this connection is known as the Cow-shark family, having one species 

 which ranges from Cape of Good Hope to California. It is named "Perlous," and is of the 

 genus Heptangus. 



AMONG some other Sharks, the PICKED DOG-FISH deserves notice, on account of the 

 curious weapons from which it derives its name. 



In front of each dorsal fin is placed a strong and sharply pointed spine, or pike, which has 

 caused the fish to receive its popular name in most parts of the coast. The word is a dissyl- 

 lable, and pronounced Pick-ed. On some of the shores it is called the BONE DOG, and on 

 others it is known by the name of the HOE. 



These spines form aggressive weapons of a rather formidable character, the fish having 

 the capability of directing a blow with wonderful accuracy. Mr. Couch says, that he has 

 known the Picked Dog-fish able to pierce a finger if laid on its head, and never to miss its 

 aim. When about to strike, it bends its body like a bow, and suddenly lashes out in the 

 intended direction. It is a very common species, especially during the herring season, as it 

 follows the shoals of those fish for the purpose of feeding on them. Even the tiny, quarter- 

 grown young, not half the size of their intended prey, instinctively follow the herrings, though 

 it is manifestly impossible that they should be able to eat them. 



The Picked Dog-fish is destructive to the fishing trade, not only on account of its large 

 appetite and the number of fish it consumes, but because it cuts the hooks away from the lines 

 with its sharp teeth. As, moreover, it, is extremely plentiful, some twenty thousand having 



