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REMARKS ON THE COMMON VIPER, VIPERA BERUS, AND 
ON ITS SUBSPECIES V. SEOANEI. 
By G. A. Bounencer. 
Ir is frequently believed that existing species can only be 
separated by the presence of gaps in the series of variations, or, 
in other words, that “good species” ought always to be sharply 
distinguishable without the interposition of any connecting 
forms ; that if two or more species are completely linked together 
they should be united, save to be distinguished as subspecies. 
However recommendable this principle may be when naturalists 
have to deal with forms of which they possess little material and 
information, it cannot always be carried out when knowledge 
attains a nearer approach to perfection, as in the case of certain 
groups of European reptiles. Since proper attention is being 
paid to the variations of the commoner forms, several species, on 
the distinctness of which no one has ever ventured to cast a 
doubt, have been found so linked together as to be in some cases 
utterly inseparable by the means of investigation at our com- 
mand. One of the most striking examples of this kind of 
difficulty is presented by the Vipers of Europe, a subject which 
has already been discussed by Bosca, Lataste, and Tourneville, 
but on which there still remains a good deal to say. 
Until a few years ago only three forms of European Vipers 
were distinguished, one forming the genus Pelias (Merrem, 1820), 
viz., P. berus, L., the two others the genus Vipera (Laurenti, 
1768), viz., V. aspis, L., and ammodytes, L. The former genus 
was characterised by the presence of three large sincipital shields ; 
the latter by the absence of these shields, the head being entirely 
covered with small scales. The two species of Vipera proper 
were distinguished by the presence in V. ammodytes and the 
absence in V. aspis of a large horn-like protuberance on the end 
of the snout. A strict examination of a large number of speci- 
mens from various localities shows, however, that the distinction 
of species is by no means so simple. I should not even allude to 
the rejection of the genus Pelias, as I go so far as to doubt the 
possibility of surely distinguishing in all cases V. berus from 
V. aspis, were it not that, in spite of the objections of recent 
