Fig. 272.—A Rattlesnake.
Fig. 273 a.—Head of Viper, showing typical triangular shape of head of venomous snake.
Fig. 273 b.—Side View, showing poison fangs; also tongue (forked, harmless).
Fig. 274.—Viper’s Head, showing poison sac at base of fangs.
Fig. 275.—Skull, showing teeth, fangs, and quadrate bone to which lower jaw is joined. See Fig. [284].