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SNAKE -VENOMS. 

 By W. Haniva, M.A., M.B. 



[Read April 11th, 1902.] 



Venomous snakes are pretty well distributed all over 

 the temperate and tropical regions of the world, with the 

 exception of New Zealand and Oceanic Islands. They are 

 divided into two great classes : — 



1. Poisonous colubrine snakes. 



2. Viper ine snakes. 



The chief aim of the paper is to draw attention to the 

 differences in the two great classes, especially as regards 

 the poison apparatus, and more particularly the venom. 



The two types to be considered are the cobra, represent- 

 ing the colubrine, and the daboia, or Russell's viper, repre- 

 senting the viperine snakes, these being the two snakes 

 with which the writer has more intimate acquaintance. 



The venom of snakes is secreted in a g-land which is the 

 homologue of the parotid salivary gland in other 

 vertebrates. It is a compound racemose gland with large 

 alveoli. These have an epithelium of short columnar cells 

 enclosing a capacious lumen, in which the secretion is 

 stored. The glands are placed one on each side of the 

 head, behind the orbit and beneath the masseter muscle. 

 In the cobra they are of very large size. The poison duct 

 passes from the anterior margin of the gland forwards 

 along the upper jaw; it is longitudinally folded on itself 

 for the greater part of its length, and lined with 

 epithelium. 



The duct has opening into it, throughout its length, a 

 series of small glands, completely surrounding it. It has 



