158 THE OCEAN. 
ynouth and contracting the muscles of the throat, the 
flesh is pursed up again into folds, and the water is 
driven, as in the former case, through the whalebone, 
which secures the food. 
The Whales, gigantic as they are, yet having little 
power of offence, find to ‘their cost, in common 
with nobler creatures, that harmlessness is often no 
resource against violence. Several species of the 
voracious Sharks make the Whale the object of 
their peculiar attacks; the Arctic Shark (Seymnus 
borealis) is said, with its serrated teeth, to scoop out 
hemispherical pieces of flesh from the Whale’s body 
as big as a man’s head, and to proceed without mercy 
until its appetite is satiated. Another Shark, often 
called the Thresher (Carcharias vulpes), which is 
sometimes upwards of twelve feet long, is said to 
use its muscular tail, that is nearly half its whole 
length, to inflict terrible slaps on the Whale; though 
one would be apt to imagine that if this whipping 
were all, the huge creature would be more fright- 
ened than hurt. The Sword-fish (Xiphias gladius), 
however, in the long and bony spear that projects 
from its snout, seems to be furnished with a weapon 
which may reasonably alarm even the leviathan of 
the deep, especially as the will to use his sword, if 
we may believe eye-witnesses, is in nowise deficient. 
The late Captain Crow records an incident of this 
kind with much circumstantiality : “One morning,” 
he observes, “during a calm, when near the He- 
brides, all hands were called up at 3 A.M. to witness 
a battle between several of the fish, called Threshers, 
or Fox Sharks, and some Sword-fish, on one side, 
