298 



ANIMAL STUDIES 



protected by bony shields, and some of them, the box-tur- 

 tles, may close their shields almost hermetically. The 

 snakes broaden their heads, swell their necks, or show their 

 forked tongues to frighten their enemies. Some of them 



FIG. 167. Noki or poisonous scorpion-fish (Emmydrichthys vulcamis) with poison- 

 ous spines, from Tahiti. 



are further armed with fangs connected with a venom gland, 

 so that to most animals their bite is deadly. Besides its 

 fangs the rattlesnake has a rattle on the tail made up of a 



FIG. 168. Mad torn (Schilbeodes furiosus) with poisoned pectoral spine. 



succession of bony clappers, modified vertebrae, and scales, 

 by which intruders are warned of their presence. This 

 sharp and insistent buzz is a warning to animals of other 

 species and a recognition signal to those of its own kind. 



