CHAPTER VI 



POISON APPARATUS— DIFFERENT KINDS OF 



POISONS 



~^HE gland which secretes the poison is a modifi- 

 ■■■ cation of the parotid salivary gland of other 

 Vertebrates, and is usually situated on each side of 

 the head below and behind the eye, invested in a 

 muscular sheath. It is provided with large alveoli 

 in which the venom is stored before being conveyed 

 by a duct to the base of the channelled or tubular 

 fang through which it is ejected. 



In the Vipers, which furnish examples of the 

 most highly developed poison apparatus, although 

 inferior to some in its toxic effects, the poison gland 

 is very large and in intimate relation with the 

 masseter or temporal muscle, consisting of two bands, 

 the superior arising from behind the eye, the inferior 

 extending from the gland to the mandible. When 

 the snake bites, the jaws close up, causing the gland 

 to be powerfully wrung, and the poison pressed out 

 into the duct. From the anterior extremity of the 

 gland the duct passes, below the eye and above the 

 maxillary bone, where it makes a bend, to the basal 

 orifice of the poison fang, described above (p. 55), 



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