10 THE OEDEE OF SNAKES— OPifZDI^. 



and, by a little attention to the subject, this may be easily done. The 

 following synopsis shews the distbiguishing characters of — 



«._NoN-YENOMors Snakes. . 3^^^ g^^^g^ 



Scales smooth, polished, not imbricated ; witliout external eyes ; tail V pjj,^g y^ gg^ 9^ 9,,^ 



very short, ending in a sharp point ... ... .•• ■■■/ 10,11,12,12a, 



■^ ^ { 126, 13, 13a. 



/" Colubrides and 

 Gape of mouth deeply curved upwards, seven or more upper and ) Tree Snakes. 

 ■,,■.■■, 1 Plate V, figs. 6, 6a, 



lower labials ( 7,7a,8,8a. 



Scales small, in more than thirty rows, more than ten labial scales r Pythons or 

 bordering the mouth above and below ; tail short and prehensile ; J p^°^ ^ fils^ 2 3 

 rudimentary limbs like spurs on each side of the vent (^ 3a, 4,' 5^5a. 



Innocuous snakes when they bite leave marks thus — 



Venomous 



Colubrine Snakes. 



Plates XI and 



XII. 



h. — Venomous Snakes. 



The gape of the mouth forming a straight line ; with upper and lower"' 

 labial shields six, and never more than seven in number ; body- 

 scales in not more than twenty-six rows ; larger teeth in front of 

 the upper jaw covered by the gums 



Venomous snakes, when they bite, leave two punctures only, thus — 



(• . ) 

 An Australian snake that is not thicker than a man's little finger, 



whatever may be its length, cannot by its bite endanger the life of an adult 



human being. 



Giinther states that "poisonous snakes are armed with a long 



canaliculated tooth in front of the upper jaw, with a duct which carries 



the poisonous fluid from a large gland to the tooth. This venom gland 



corresponds with the parotid salivary gland of the mammals, and is 



situated on the side of the head, above the angle of the mouth ; it is 



invested by a dense fibrous sheath, which is covered by a layer of muscular 



fibres. At the moment the snake opens its mouth to bite, these muscles 



compress the gland, and force its contents through the excretory duct into 



the channel of the venom tooth, whence it is injected into the wound. 



The structure of the venom tooth is not the same in all poisonous snakes ; 



in some it is fixed to the maxillary bone, which is as long, or nearly as 



long as in the non-venomous snakes, and generaUy bears one or more 



ordinary teeth on its hinder portion. The venom tooth is fixed more or 



less erect, is not very long, and its channel is generally visible as an external 



groove. The poisonous snakes with this dentition, have externally a 



more or less striking resemblance to the non- venomous ones; and on 



