298 THE LIVING ANIMALS OF THE WORLD 
animal for its size could scarcely be conceived; and I have seen one, in the Indian Ocean, 
fling itself three or four times in succession out of water like a salmon, striking the surface 
each time as it fell back with a report like that of a gun. No one appears to have explained 
whether performances of this sort are due to mere playfulness, or, as seems more probable, to 
the attacks of parasites or such larger enemies as sharks or “killers.” I have also seen four 
thresher-sharks leaping out of water, and falling with a loud blow on the whale’s back; but 
the victim lay quite still in this case, and may in fact have been worn out before we came 
upon the scene. I wish to add that I took the word of the skipper, himself an old whal- 
ing-captain, for their identity as threshers. The dazzling sun shone full on them, and on 
the sea between, and it was impossible, even with the ship’s telescope, to recognise them 
with any accuracy. The 
f Ree j cachalot has a_ very 
different profile from what 
| any one who had seen 
only its skull in a 
museum would be led to 
expect, for the sperm- 
cavity in the forehead 
is not indicated’ in the | 
bones. The structure of 
the’ head enables the 
animal to drop the lower 
jaw almost at right angles 
7 to the upper; and Mr. 
ELLIOTT’S DOLPHIN Frank Bullen quotes, «in 
One of the commoner Indian species his fascinating ee Cruise 
ee _.., of the Cachalot,” the 
| current belief that it does 
so to attract its prey by 
the whiteness of its teeth 
and palate. Although 
both fishes and_ cephalo- 
pods are very curious, 
even to their own destruc- 
tion, it is doubtful 
whether the whale could 
not catch its food more 
l rapidly by swimming 
Y ie is open-mouthed through 
Photo ‘A. S. Ri dland &* Son = ‘ye 
voy ai ‘ RISsO’S DOLPHIN the acres of floating squid: 
About 13 feet in length, found in almost all oceans encountered all over the 
warmer waters of the ocean. 
The NARWHAL, an arctic type, may be distinguished from all other cetaceans by the single 
spiral tusk in the left side of the head of the male. Sometimes the right tusk grows as 
well, and either may attain a length of as much as 8 feet; but in the female both teeth 
remain undeveloped. 
The COMMON PoRPOISE of our own seas, distinguished by its rounded head from the 
equally common beaked dolphin, is too familiar to need much description. It grows to a 
length of § or 6 feet, and is dark in colour on the back and white beneath. Its conspicuous 
back-fin is always recognisable when it gambols with a herd of its fellows; and a line 
of these sea-pigs, a mile or so in length, is no uncommon sight, their presence inshore being 
indicative on some parts of the coast of the coming of east wind. The porpoise, which has, 
