346 THE POPULAR SCIENCE MONTHLY. 



on the under side of the head, and is furnished with teeth which are 

 adapted to crushing crustaceans and similar creatures upon which they 

 feed, and not for tearing flesh. Behind the eyes they have two large 

 blow-holes. 



The common saw-fish reaches a length of twelve to fifteen feet, of 

 which the saw is about one third. It carries a much uglier weapon 

 than the sword-fish, for along the edges of its beak are set pointed 

 conical teeth, two or three inches apart. The number of teeth on each 

 side varies from twenty to thirty. The "saw" is not used by being 

 drawn backward and forward : in killing small fishes for food, the 

 saw-fish charges among them, striking to the right and left with the 

 serrated edges of its beak, and generally succeeds in disabling a con- 

 siderable number. When a whale is the creature attacked, this ter- 

 rible weapon is plunged into the soft, blubber-covered body of the 

 cetacean, the saw-fish avoiding by superior agility the strokes of the 

 tortured animal's tail, any one of which would end the career of the 

 daring gladiator. His weapon is often found deeply imbedded in the 

 side of a shij), and even after the death of its original owner the 

 beak may still inflict grievous wounds, for the Polynesians are fond of 

 using it as a sword. 



The narwhal belongs to the order of whales, and hence is not a fish. 

 When full grown it reaches a length of about sixteen feet ; it has the 

 rounded body and horizontally flattened tail of the whales, but its 

 head is small and rounded more like that of the seal. It inhabits the 

 Arctic seas, and is a valuable game for the Greenlanders, as its flesh is 

 much prized by them, and it yields a moderate quantity of very deli- 

 cate oil. The color of its skin is gray, varied by darker streaks and 

 patches, and shading from almost black above to white underneath. 

 The curious horn to which the narwhal owes its fame is not a pro- . 

 longation of the jaw as in the case of the fishes just described, but is a 

 long tooth, like the tusks of the elephant or the boar. In the upper 

 jaw of the young narwhal are found two small tusks, which in the 

 female regularly remain undeveloped throughout her life. In the male 

 the left tusk grows into a spirally grooved rod, sometimes attaining 

 the length of ten feet. A large narwhal's tusk has no small commer- 

 cial value, for the ivory is very hard and solid, will take a high polish, 

 and keeps its beautiful whiteness a long time. Several ingenious specu- 

 lations have been made in regard to the use of this remarkable growth ; 

 killing fish for food and breaking breathing-holes through the ice are 

 two uses suggested which fail to account for the long tusk being con- 

 fined to the males. The females certainly can not live on air alone, 

 nor without air, and they can not count on always having a male near 

 to wait upon them. It is more probably to be accounted for by the 

 same reasons which explain the possession of horns, tusks, or mane by 

 the males only of some land haammals. Rarely the right tusk is de- 

 veloped instead of the left, and sometimes the female has a weapon 



