DENTITION. 363 



Ics exposer a dcs injures! ^ This, ho^^■cvcr, Is the case with 

 the Viperina only. It is common, for the reasons just now 

 assigned, to find the cobra classed among the vipers, in some 

 popular encyclopedias ; and in one, a valuable and generally 

 trustworthy American edition of 1875, we read, 'moveable 

 fangs like the cobra, viper, and rattlesnake.' A cobra has 

 not moveable fangs. Another, an excellent English edition, 

 but of not very recent date, includes all venomous snakes 

 under the head of ' vipers ; ' a third in general terms states 

 that 'venomous snakes have no teeth in the upper jaws, 

 excepting the fangs, and that the opening of the mouth 

 brings these into position ; ' whereas it is now known that a 

 viper can open its mouth and yet keep its fangs depressed 

 and sheathed. In several other enc}'clopedias the description 

 of fangs is suited to vipers only. 



It is not necessary to designate names, as these things 

 will be set right in the new editions. They are mentioned 

 more with a view to show that ophiolog}^ has advanced with 

 rapid strides of late, rather than presumptuously to criticise 

 our standard works. Perhaps in another twenty years my 

 own poor efforts will be exposed as ' old-time miscon- 

 ceptions.' 



The renewal of poison fangs is another subject of interest 

 to ophiologists : how the next supplementary fang becomes 

 fixed, ancJiyloscd to the jaw-bone ; and how and when the 

 connection with the poison duct is completed. I\Ir. Tombes, 

 in a paper read before the Royal Society in 1875, describes 

 a 'scaffolding' of bone thrown out to meet and grasp the 



^ Essai sur la physioguoviic dcs sirpcnts, par Herman Schlcgcl. Amsterdam, 

 iS37. 



