VIPERA ECHIS. 93 
to bite. Its movements are exceedingly quick. For effects 
of the poison, see page 89. 
No. 3. Vipera Echis Variegata, another South American 
variety, only differs from the preceding in the variegations of 
its skin, which are marked by black lozenge-shaped macule 
upon a lead-colored ground, extending down the centre of 
dorsum from neck to tail. 
Fourth Species—V1PERA PSEUDECHIS MAJOR, is very abun- 
dant in the highlands. 
Length from 75 to 200 centimetres. Body 3 to 5 centimetres thick. 
Throat and dail long, latter slender; dorsum freenish-brown, marked 
with macule not of a uniform size, and of irregular shape, covered 
with 26 to 40 rows of semi-oval lanceolate scules. Belly light lead color. 
The species which are found at a height of from 500 to 
1500 metres above the level of the sea are the most venomous; 
those occurring higher up being provided with a much less 
active poison. Its Spanish names are Taya, Taya-Equis, 
Taya-Rabona. 
Seventh Species, VIPERA ACTRACTASPIS IRREGULARIS, has 
the fangs so long that they almost touch the angle of the 
mouth. 
Eleventh Species, VIPERA LACHESIS BUFOCEPHALUS, called 
Frog-headed Mapana, or Cabeza de Sapo. 
Length from 8 to 6 feet; head wider than the thickest part of the body, 
triangular shaped; the sides of the mouth are covered with 8 large 
irregular-shaped scales on each side of the upper jaw; the upper ante- 
rior edge of the head, from one eye to the other, has its periphery 
marked by a series of scales folded over each other, forming a sort of 
ridge, which lies in the same plane as the top of the head, which is per- 
fectly level, and covered with exceedingly minute, imbricated scales, 
that increase in size towards the neck, and are of a greenish dirty-brown 
color, like the back of a frog; hence its name. Belly of a light lead- 
color; its back is marked with a row of rhomboidal macule of a dark 
