334 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 

 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 

 to the tipper; and Mr. 

 Frank Bullen quotes, in 

 his fascinating " Cruise 

 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 

 rapidly by swimming 

 open-mouthed through 

 the acres of floating squid 

 encountered all over the 

 warmer waters of the ocean. 



Phut t, A. S. Rutland & Sit* 



ELLIOTT'S DOLPHIN 



One cj t'le commoner Indian species 



Fhatt b; A. S. Rutland <V Sim 



RISSO'S DOLPHIN 



About IJ feet in length, found in almost all oceans 



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 5 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, 



