276 



INTRODUCTION TO ZOOLOGY. 



venomous is nearly as four to one. This is contrary to popular 

 opinion, and it was especially so in the " olden time." Thus, 

 whenever Shakspeare mentions one of those animals, it is 

 always as a creature to he shunned as hateful or venomous: 



" He is a very serpent in my way; 

 And wheresoe'er this foot of mine doth tread, 

 He lies before me." KING JOHN, Act iii. scene 3. 



The gigantic Boa-Constrictor "belongs to those which are 

 not venomous. It kills its prey hy the enormous compression 

 it exerts when coiled round the body of its victim, which it 

 then proceeds to swallow entire. The teeth are sharp, point 

 backwards, and thus retain the food. And here comes into 

 use a curious and bountiful provision with which snakes are 



furnished. The lower jaw 

 is not united to the upper; 

 it is hung to a long, stalk- 

 shaped hone, upon which 

 it is moveahle (Fig. 224); 

 and this hone has also a 

 power of motion, being 

 attached to the skull by 

 muscles and ligaments. By 

 means of this apparatus, 

 which is common to all true Serpents, they can swallow ani- 

 mals larger than themselves. This being done, they remain 

 P m in a quiescent state until 



digestion is completed, 

 and the calls of hunger 

 again excite them to 

 exertion. 



In addition to this 

 elaborate contrivance, 

 the venomous tribes are 

 furnished with poison- 

 fangs, * 'constituting per- 

 haps the most terrible weapons of attack met with in the 

 animal creation"! (Fig. 225). They are two in number, 

 fixed to the upper jaw, or, to use more precise language, one 



* Fig. 225. p, poison gland; its duct terminates in the large moveable tooth or 

 fang/y m, muscles which raise the lower jaw and compress the poison gland. 



Fig. 224. SKULL OF RATTLE-SNAKE. 



Fig. 225. POISON APPARATUS OF RATTLE- 

 SNA KK.* 



f Jones's Outline of the Animal Kingdom. 



