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CHAPTER: Tit. 
DESCRIPTION “Or THE PRINCIPAL... SPECIES NOR 
POISONOUS SNAKES. THEIR GHOGRAPHICAL 
DISTRIBUTION. 
Poisonous snakes are especially common in the tropical zones 
of the Old and New Worlds. The species found in Europe are 
but of small size and not very formidable. In hot countries, on 
the other hand, they attain large dimensions, their venom is much 
more active, and, although they hardly ever attack man, and in 
most cases avoid him, they cause a considerable number of fatal 
accidents. 
It is sometimes a rather difficult matter to recognise from the 
mere appearance of a snake whether it is poisonous or not. Natu- 
ralists themselves are occasionally deceived. It is therefore useful 
to learn to distinguish the most dangerous species by their external 
characters, and to know in what countries there is a risk of their 
being encountered. 
A—EUROPE. 
Of the continents of the Old World, the poorest in poisonous 
snakes is Europe. The only species found there are a CŒLOPELTIS 
(belonging to the Sub-family Dipsadomorphine of the Opistho- 
glypha), and certain VIPERINÆ, which rarely exceed 75 centimetres 
in length. 
Ca:LOPELTIS, the cranial skeleton and head of which are repre- 
sented in fig. 20, is characterised by a narrow, concave frontal shield, 
