ANIMAL SELF-DEFEXSE. 



605 



effect is a saw-cut. It then acts as a veritable saic. But it seems ab- 

 surd for an animal to carry teeth on the outside of his nose. 



With another shark the tail is a weapon, as it is with the whale 

 also. The tail of the thrasher is extremely large, and can deal severe 

 blows. The thrashers have been known to attack the whale when the 

 latter is at the surface. It is conjectured that the thrashers and the 

 sword-fish form a conspiracy against the whale, and, while the latter 

 prevent the whale from diving, the former leap out of the water and 

 brincr their huge tails down on the naked back of the whale with a tre- 

 mendous slap that can be heard a long way. Probably the whale is . 

 more frightened than hurt. 



Some rays or skates have the tail long and whip-like. It is covered 

 with sharp spines, and forms an effective instrument for either strik- 

 ing or grasping. These spines produce severe inflammation, and are 

 greatly dreaded by fishermen. The larger ones are much used by sav- 

 ages for edging weapons. It is supposed that the whip-ray seizes an 

 enemy, or its prey, with its tail, and kills it by the cutting spines on 

 its tail, and by pressing it against the barbed spine situated on its back. 

 These spines are commonly used as spear or arrow heads by the sav- 

 ages of the South Sea. 



Some small creatures have forceps or jaws as weapons. Those of 

 the lobster are modified feet, while those of the beetle are mouth-parts. 



The most elaborate organs of defense are found in the lower forms 

 of life. And at near the lowest point in the animal scale we find an 

 apparatus exceedingly complex and efficient. This is the "nettling- 

 threads," "lasso-cells," or cnidcBj which give the hydra, jelly-fish, and 



Fig. 9. Lasso-Cell, coxtaetlsg Barbed Filament. (.After Gosse.) 



polyps their power of stinging. They are also possessed by the cri- 

 noids, some naked sea-snails, and some sea-worms. Like manv other 

 weapons, they are used to subdue prey as well as to repel enemies. 

 These creatures are soft and delicate, and would seem to be the easiest 

 food for other animals. The cnidm are probably their only defense, 

 but they seem quite sufficient. A chapter would be required to give a 

 full description of these wonderful weapons. The instrument consists 

 of a hollow filament, coiled in a sac, the whole of microscopic size. 

 The sacs are commonly on the surface of the tentacles and other free 

 surfaces of the body. In some species they are collected in thread- 



