SNAKES VENOMOUS AND NON-VENOMOUS. 143 



Tree-snakes. The South-American Rat-snake (Spilotes variabilis) 

 presents a shining black, barred with brightest yellow, and the 

 East-Indian Coryphodon blumenbachii glistens like silver. 



It is difficult to see how or why an idea should have originated 

 that all those having short or blunt tails belong to the dangerous 

 class. No basis whatever exists for such a dictum ; unless it be 

 that in many tropical countries a great horror prevails of certain 

 creatures which are reputed to be fearfully venomous, and which 

 certainly have such very blunt tails that they are often known as 

 Two-headed Snakes, being accredited with a head at either 

 extremity, and the power of going ahead and astern with equal 

 facility when burrowing in the earth or mud in which they are 

 found. These really are not snakes at all, but Amphisbamce, and 

 perfectly incapable of doing any mischief. A thick upper jaw looks 

 bad, but is not to be trusted as a universal indication of danger. 



All snakes which wear any peculiar external appendages 

 may certainly be looked upon with well-grounded suspicion, but 

 these are comparatively so few in number that such appendages 

 can be regarded in this light as little more than distinguishing 

 marks of certain species. I am not aware that there are any * 

 harmless horned snakes, though there are some which have 

 something or other analogous to such an ornament— for instance, 

 the Dryiophidce, with their elongated, pointed snouts, and the 

 Heterodons, in which the rostral shield is thickened into a promi- 

 nent, recurved trihedral pyramid. A horny or bony appendage 

 to the tail should also put us on our guard, whether it assumes 

 the form of the rattle belonging to the many different genera 

 of Rattlesnakes, or the claw-like termination of the Curucucu, 

 or the Lance-headed Snakes. Of less diagnostic value is' 

 the possession of an expansile hood— though, naturally, in all 

 these cases we should be guided according to the country in which 

 we happen to be at the time, and the reptiles we may expect to 

 meet there. The Indian and Egyptian Cobras, and the Hamadryad 

 are the hooded snakes of common notoriety, but there are other 

 less celebrated ones in which the dilatation is not so well-marked; 

 nor is this characteristic confined to poisonous ones. The 

 Caninana (Spilotes pcecilostoma) of Brazil hisses, rears its head, and 

 spreads a very respectable hood when angry. The word "hood," 

 however, hardly conveys a correct impression of the appear- 

 ance to anyone who has never witnessed the action; "fins" 



