366 



REPORT OF NATIONAL MUSEUM, 1893. 



there are similar fangs, but inucli larger, and differing from those ot 

 the Ulaps by being folded up toward the palate, somewhat like the 

 bhides of a jackknife wlien not in n<e. This must not be understood 

 to mean that the fangs themselves ;iie movable; on the contrary, the 



Fig. 11. 



SKULL OF RATTLESNAKE, I'UO.M AUOVE. 



(After Jan.) 



Fiji. U'. 



SKULL OF BATTLESNAKE, FKO.M .s|i)i; 



( After Jan. ) 



viper's faugs are as solidly fixed in their sockets as are those of the 

 -tJlap.s, \n\t while iu the latter (see tig. 3) the maxillary bones, into which 

 the fangs are fasteued, are elongated and horizontal, as in the harmless 

 snakes (see fig. 4), in the Crotalids they are extremely shortened and 



higher than long, so as to appear in a 

 vertical position. In the former the 

 fangs are consequently inserted nearly 

 at right angles, like the pickax on its 

 handle, while iu the latter the fang 

 more nearly represents the blade, and 

 the jawbone the handle of a knife, and 

 it is tlie jawbone which is movable in 

 the vertical plane, not the fang ahine. 

 In order fully to understand the 

 mechanism in question, it is necessary 

 torememberthat the bones of the head 

 of nearly all snakes (figs. 11-13) are so 

 loosely joined together as to allow a 

 most extraordinary amount of move- 

 ment and distention. Elastic ligaments connect bones which in other 

 animals are either grown solidly together or articulated by means of 

 close joints, hence a snake is capable of swallowing a prey many times 

 as thick as the snake's own body. 



As already noted, the upper jawbones (maxillaries) are situated ver- 

 tically, one on each side of the anterior portion of the mouth, the hollow 

 fang being fastened into the lower end of the bone. On the outer face 



Fig. 13. 



SKULL OF RATTLESrrAKE, FROM BELOW. 

 (After Jan.) 



