THE PORBEAGLE SHARK. 181 



shark is a still more dangerons enemy, and it 

 is common for it to pass in succession along the 

 whole length of the net, cutting out, as with 

 shears, the fish and the net that holds them, 

 and swallowing both together." 



Other true sharks, as the porbeagle, (Lamna 

 cornubia,) and the Greenland shark, (Scymnus 

 borealisy) so well known to the Greenland 

 fishers as the deadly foe of the whale, are 

 sometimes also to be seen. The latter species 

 is extremely tenacious of life, and its ferocity 

 is dreadful ; it attacks the whale, rending out 

 with every snap large masses of the whale's 

 flesh, while the latter lashes the water with 

 agony or vain efforts to drive away his foe. 

 We may here observe a singular circumstance, 

 connected with the sharks of the temperate and 

 warmer latitudes, as the white shark and the 

 blue shark, that they are often seen attended 

 by two or more small fishes, called pilot-fishes, 

 (Naucrates ductor,) between which and them- 

 selves a singular friendship subsists ; they have 

 been known to interpose between their friend 

 and the baited hook, and running against his 

 muzzle turn him from it. On the other hand, 

 perhaps, where they see no danger, they will 

 direct him to the bait, and even cling to him 

 as he is hoisted up on deck. This singular 



