248 A MANUAL OF DENTAL ANATOMY. 



Some of the harmless snakes, however, have particular 

 teeth which are developed to a greater length than the rest, 

 and others have the posterior teeth on the maxillary bones 

 grooved ; but the statement that this grooving serves to 

 convey an acrid saliva into the wound inflicted rests on in- 

 sufficient foundation. The poisonous snakes are charac- 

 terized by a shortening of the series of teeth carried upon 

 maxillary bone, and by the front tooth of the series being- 

 developed to much greater length than those which lie 

 behind it. Thus Hydrophis, a genus of poisonous sea-snakes, 

 has five or more teeth upon the maxillary bone, the fore- 

 most of which is much the largest, and this largest tooth is 

 so deeply grooved upon its anterior surface as to be converted 

 into a tube, the tube serving to convey the poison into the 

 wounds inflicted by it. 



Poisonous snakes which have several teeth upon the 

 maxillary bone for the most part present some little external 

 resemblance to the harmless snakes, and are called "colu- 

 brine poisonous snakes " (coluber being the name of a genus 

 of harmless snakes) ; they present transitional characters 

 between these and the more specialised or "viperine" poison- 

 ous snakes. The Cobra is a familiar example of a colubrine 

 poisonous snake, and almost all the venomous snakes of 

 Australia belong to this group. Their poison fangs are not 

 very long, and they remain constantly erect, being anchy- 

 losed to the bone (the maxilla) which is long and not move- 

 able, and which also carries a varying number of small 

 insignificant teeth behind the poison fang. 



In the viperine poisonous snakes (Puff-Adder, Rattle- 

 snake, Vipers, &c.,) the poison apparatus is yet more 

 specialised. The maxillary bone carries no teeth at all 

 behind the poison fang ; it is so reduced in length as to be 

 of squarish form, and is so articulated to the skull as to be 

 movable. 



The poison fang is of great length, so that if constantly 



