THE WHALES, DOLPHINS AND MANATEES 34* 



diving, racing through the water, and giving the most wonderful 

 exhibition of their perfect adaptation to their environment. 



The Narwhal, or Sea-Unicorn (Monodon monoceros), is a most 

 remarkable whale on account of its so-called horn, or rather tusk, 

 or, still better, enormously developed canine tooth, which looks 

 like a solid rod of ivory, tapers from root to tip, has a kind of 

 striated spiral surface, and is often from five to seven feet or more 

 in length, so that the Narwhal is easily the proud possessor of the 

 longest tooth in the mammalia. The adult animal varies from ten 

 to sixteen feet in length, and has a blunt, short head, no dorsal 

 fin, and very small flippers. It is essentially a northern form, 

 insomuch that it frequents the coasts of Greenland, Spitzbergen, 

 and Siberia, occasionally appearing off the coasts of Scandinavia 

 and Britain. The Narwhal possesses only two teeth the greatly 

 developed or left canine, and within the jaw on the right side the 

 rudiment of a similar tooth which seldom is protruded ; although 

 in certain rare cases, instead of one, the two tusks are developed. 

 The great single tooth in the upper jaw is quite rudimentary in 

 the female. 



The Whalebone Whales (Mystacoceti) are distinguished from 

 the toothed whales by their upper jaws being provided with 

 baleen plates instead of teeth ; in early life, however, rudimentary 

 teeth occasionally are present, but these never project beyond the 

 gums. Their skulls are symmetrical, and not distorted as in the 

 toothed Whales, and there is a double aperture to the blow-hole. 

 The separate bones in the lower jaw arch widely outwards. The 

 upper jaws are relatively narrow and project forwards at the 

 same time with a great fore-and-aft arch, but are encompassed 

 by the lower jaw arches. The head is proportionally of immense 

 size, and admits of an extraordinarily capacious mouth. The 

 palate is but a narrow median line, and the huge mouth little else 

 than an enormous dome of whalebone plates whose inner lower 

 margins are frayed. Thus, while the whalebone is longer than the 

 depth of the closed mouth, it nevertheless is accommodated by 

 being tucked in below at its flexible extremities. A great, broad, 

 massive tongue fills the interspace between the lower jaws. The 

 whalebone blade of dense horny-like material is in the early stages 

 composed of a brush of hair-like bodies, which, lengthening, solidify 

 and assume the hard horny appearance afterwards known as "the 



