ORAL EQUIPMENTS. 47 



snakes. The "Cobra," and most of the Australian species 

 present these intermediate characters. 



Harmless snakes ! save the mark — for who would call a 

 Boa-Constrictor harmless, or pine for him as a bedfellow — 

 have an endless succession of teeth arranged as follows : one 

 row in the lower jaw, and two in the upper. One of these 

 two upper rows is arranged on the maxillary bones, and the 

 other, the internal, on the palatine and pterygoid bones. 

 They are all anchylosed to the bone, and are strongly re- 

 curved backwards. The lower row fits in between the two 

 upper rows. 



Now, starting with a tooth from a harmless snake, we 

 find it pointed and recurved, with perhaps a more or less 

 deep groove down its external surface. 



A Colubrine snake has the groove nearly closed into a 

 tube, and in a true viperine snake, e.g., a rattlesnake, it is 

 closed completely with the pulp chamber, as it were wrapped 

 round the poison tube. 



The tube opens on the external surface of the fang, 

 a little way from the end ; this arrangement precludes the 

 possibility of it getting stopped up when it pierces its victim. 

 Hypodermic syringes are made on this plan. 



Now I mentioned a structure called a " quadrate bone." 

 I wish you to take special note of this, for it is one of those 

 significant links in the chain of existence, which "he who 

 runs may read." It is peculiar to reptiles and birds, and for 

 these creatures which swallow their victims whole is a most 

 useful, nay, necessary structure. 



You will naturally expect this bone to be enormously 

 developed in the typical viperine snakes, when I explain that 

 its use is to enable the creature to open its mouth wider than 

 can be attained in the way usually found in vertebrates. 



A snake does not " swallow its victim, as we do," but gets 

 outside it " by the movements of the quadrate bone." 



I think it would perhaps be going a little too deeply into 

 the subject for a general audience like the present, to enter 

 into the minute anatomical details ; for to those unfamiliar 

 with the technical terms, it would perhaps rather confuse 

 than elucidate my meaning. What I do want you to carry 

 away in your memories is a general idea of the mechanism 

 of the jaws of a viperine snake. I will therefore dismiss the 

 names of the individual bones and muscles, in my short 

 explanation. 



AVhen a venomous snake is at rest its poison-fang lies 

 backwards in the mouth. By the movement of opening the 



