THE WHALE TRIBE. 1t3 
then dive down, as they chase each other in their gam- 
bols. The Dolphin is quite as sportive as the Porpoise, 
and much more agile. It often follows ships in numer- 
ous herds, executing its playful movements. The stories 
about the beautifully-changing hues of the dying Dolphin 
are untrue; this voracious animal is altogether unpoet- 
ical even to death. Its colors are black and white, and 
the only change which occurs is that the black, after a 
time, becomes brown, and the white gray. 
194. There are some aberrant genera of the Dolphin 
family. One of the most remarkable we have in the 
Narwhal, or Sea Unicorn, as it is commonly called, Fig. 
94. Its body is from thirty to forty feet long. It has 
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. / 
Fig. 94.—The Narwhal. 
a long, straight, pointed tusk, from five to ten feet in 
length. It really has two tusks, but only one of them 
becomes long, the other not projecting sufficiently to be 
seen. There is much question about the use to which 
the animal puts this tusk. Some suppose that its chief 
purpose is to dig up sea-weed for focd. Others suppose 
