606 THE POPULAR SCIENCE MONTHLY, 



like magazines which are shot out of the body-walls. Upon irritation 

 this hollow thread is thrown out of the sac to a great length, by ever- 

 sion. It is turned inside out, and then exposes a barbed surface. They 

 penetrate the soft tissues of the animal attacked, and convey a poison 

 fatal to small animals. Any bather who has ever been stung by a 

 jelly-fish can give a satisfactory account of the effect of these weap- 

 ons. There is no doubt that a man would be completely and quickly 

 paralyzed if entangled, in a nude state, among the tentacles of the 

 larger jelly-fishes. 



The stings of insects are more familiar, but still very wonderful. 

 In the sting of the honey-bee " we see an apparatus beautifully con- 

 trived to enter the flesh of an enemy ; two spears finely pointed, sharp- 

 edged, and saw-toothed, adapted for piercing, cutting, and tearing ; 

 the reversed direction of the teeth gives the weapon a hold on the 

 flesh, and prevents it from being readily drawn out. Here is an elab- 

 orate store of power for the jactation of the javelins, in the numerous 



/ / 



Fig. 10. Barbed Case of Everted Settling-Thread. (After Gosse.) 



muscular bands ; here is a provision made for the precision of the im- 

 pulse ; and, finally, here is a polished sheath for the reception of the 

 weapons and their preservation when not in actual use. All this is 

 perfect ; but something still was wanting to render the weapons effect- 

 ive, and that something your experience has proved to be supplied." 

 This is the poison, which has also a complex apparatus for its secretion 

 and ejection. This sting is a modified ovipositor, and possessed only 

 by the females, or neuters, which are undeveloped females. The male 

 insect is always a mild and inoffensive creature. 



Scorpion-stings are similar to those of insects in position and use, 

 but are unlike in origin and development. 



The poison-fangs of venomous snakes are modified teeth. They 

 are so attached that when not in use they lie in a fold in the upper 

 jaw. The poisonous snakes have broad heads, on account of the mus- 

 cles which control the fangs and the large glands which secrete the 

 venom. The latter is a sort of saliva, probably charged with ferment- 

 ing organisms, which are harmless in the food-canal, but which in the 

 blood multiply with amazing rapidity. The poison is conveyed to the 

 wound by a groove in the side of the fang. 



The fangs of spiders represent the antenna? of insects. They are 

 tubular, for conveying venom, and jointed. The point or terminal 

 joint when not in use shuts into the basal joint, like the blade of a 



