98 OPHIDIANS. 
A second variety of No. 18 is Vipera Clotho. cornuta, Das 
Adder or the River Jack, sometimes taken for the Cerastes. 
It is also called the Plumed Viper or Hornsman. 
No. 19. Vipera Cerastes Caudalis, the Cerastes or Horned 
Viper, is one of the most vicious-looking reptiles in existence. 
Its general color is that of a frog, variegated with irregular-shaped 
bistre-colored maculz and spots on its dorsum ; length from two to three 
feet; trunk very thick and slightly carinated; head cordate, and the ros- 
trum is provided with two short, upright, tentacula-like appendages 
called horns. 
No. 20. Vipera Cench. Piscivorus, is also called Cotton- 
mouth or Water Moccasin. This snake’s poison sometimes 
produces death and at other times it does not, consequently it 
is little feared. 
No. 23. Vipera Acanthophis Antarctica, is also called 
Death Adder or Death Viper, in Australia. 
Other snakes occur which are known to belong to the genus 
Viperide, but those given are the only varieties yet classified, 
making a total of 25 species, composed of 69 varieties, &e. 
The Amphisbene of Buffon’s classification has been ex- 
cluded from the family of Ophidians by later naturalists, as 
belonging more properly to that of the Earth-worms, but 
some of the species of this genus are found in South America, 
particularly in the forests of the great Atrato Valley and of 
the Isthmus of Darien, that are known to be exceedingly 
venomous. F 
One variety, occurring also in Brazil, is the Amphisbene 
Vermicularis (Wagler, Mure), signifying “worm snake, that 
moves with equal facility forward or backward,” is called 
Tatacoa, Culebra ciega, Tatacua, Sin ojos, Culebra de dos 
Cabezas, Culebra gusano. The variety described by Dr. Mure 
is, Viz. : 
