The Poisonous Snakes of British Guiana. 33 
the scales are imbricated, being more elongate than 
tuberculate. 
The colour of this species is very variable, ranging 
through grey, brown, reddish and yellow, or a mixture of 
them. The rhombs are sometimes represented, but 
always faintly so — triangular spaces, outlined by paler or 
darker streaks, and with the apices above, being the 
most common — or the body may be simply spotted or 
slashed with lighter or darker tints. The under side 
may be uniform, or spotted, or blotched and speckled. 
In very young specimens, the end of the tail is yellowish- 
white from birth, and the general marking is much 
deeper and richer than in the adults. 
Full grown specimens reach a length of about five 
feet, the females being much stouter in proportion than 
the males. The number of young at a birth, from ob- 
served cases, appears to range from 20 to 30, as in the 
rattlesnake, but the young labarrias are much smaller in 
proportion, corresponding to the markedly thinner build 
of the body in the two species. 
As already mentioned, this is the commonly distributed 
forest or bush viper. Many harmless colubrine snakes 
and some of the boas, which possess some resemblance 
to it in markings, are frequently mistaken for it — mis- 
takes that are very likely to be confirmed in the mind of 
the observer by the fa6l of the more or less severe pain 
and swelling which temporarily follow the bite of many of 
the colubrines with elongated and enlarged posterior 
teeth. One of these latter (Helicops angulatus) goes 
by the common name of Water Labarria, and on this 
account bears an unjustly bad reputation. 
The three vipers above described are stri6lly terrestrial 
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