2 24 SNAKES. 



not strictly a water snake, it much frequents it, and glides 

 through it with ease, the more remarkable because, in com- 

 mon with those other * horned vipers ' of Africa, it has a 

 short, insignificant little tail, which can be of little use as a 

 propelUng power. Altogether, it is one of the ugliest and 

 most ferocious-looking of the whole serpent tribe, with a 

 thick, heavy body, a dingy, rough exterior, and strongly- 

 carinated scales. Excepting in colour, and a more horizontal 

 inclination of its horns, it is not unlike the V. nasicornis of 

 the coloured illustration, chap, xviii. 



While all the Hoinalopsidce or true fresh-water snakes are 

 innocent, there are many other venomous kinds known as 

 * water serpents,' both in Africa and America. For example, 

 the * water viper,' or ' water moccasin,' Cenchris piscivorus, 

 whose aquatic and fish-eating propensities were described in 

 the chapter on Tails. This ' thorn-tail ' viper has not, how- 

 ever, the nostrils of the true fresh-water snakes or Hoina- 

 lopsidcB. In Australia also are several poisonous species, 

 known vernacularly as ' water snakes ; ' but strictly speaking, 

 and on the authority of Giinther, the true Homalopsidce are 

 all non-venomous. 



To describe these more minutely from Giinther, Krefft, 

 and Dr. E. Nicholson, ' they have a body moderately cylin- 

 drical, a tail somewhat compressed at the root, and more or 

 less prehensile. Many of them have a distinctly prehensile 

 tail, by which they hold on to projecting objects ; ' and in 

 times of storms and strong currents we can imagine the 

 importance of this security to them. Their eyes, though 

 prominent, are small, and thus less exposed to injury ; and 

 the nostrils, as already stated, are on the upper surface of 



