GENERAL CLASSIFICATION OF POISONOUS SNAKES 



prey, but in order to deal it a mortal blow by 

 into its flesh. 



In the normal position they lie almost 

 horizontally, and exhibit no mobility of their 

 own. But, when the animal prepares to 

 bite, their erection is effected by the snake 

 throwing its jaw back ; and this movement, 

 which is always very sudden, enables it at 

 the same time to compress its poison- 

 glands, by the aid of special constrictor 

 muscles. 



On examining the various species of 

 poisonous snakes, we observe very sharply 

 marked differences in the arrangement and 

 dimensions of the teeth. Thus, in the 

 ViPERiDJS they are long, extraordinarily 

 sharp, and capable of producing deep wounds 

 (fig. 2, A, and fig. 3). They are traversed 

 by an almost completely closed canal, from 

 the base, which communicates with the 

 poison-duct, to the neighbourhood of the 

 point, where it opens very obliquely on the 

 convex surface (fig. 3, a and d). 



In the ElapincB sub-family of the Colu- 

 bridcc, and especially in the HydrophiincE, 

 the teeth are much shorter and simply 

 grooved or canaliculate ; that is to say, the 

 canal communicates with the exterior 

 throughout its extent by a narrow slit, 

 which traverses the entire convex surface 

 of the tooth (figs. 4, 5, and 6). 



It does not follow from this that the 

 the bites of these reptiles are less dangerous; 



mjecting the venom 



Pig. 4. — B, Fang of one 

 of the ColubridiE {Naja 

 tripudtans) ; E, transverse 

 section. 



c 



Fig. 5.— c, Fang of one 

 of the Hydrophiince (Hydr- 

 opldspelamis); p, transverse 

 section. 



Fig. 6. — Three transverse 

 sections of a poison-fang 

 of one of the Colubridce, 

 through A A, B B, c c ; p p, 

 pulp cavity ; v v v, poison- 

 canal (groove). (After C. J. 

 Martin.) 



