258 THE ZOOLOGIST. 



For while it is generally true that a large horizontal implies also 

 a large vertical range, the causes which have led to this are by 

 no means the same in all species. As at the high altitudes 

 where V. berus is often found, its usual food — mice and other 

 warm-blooded animals — no longer exists, it is obliged to content 

 itself with a diet of the equally hardy L. vivipara, which will 

 account to some extent for its dwarfed size. 



There is little modification in the colour of this species during 

 the growth of the individual, the adults remaining almost as 

 brightly-coloured as the young. Belying entirely on its venom 

 for self-defence, it has no need of positive protective colouring, 

 as has been maintained, and it is pure chance if its tints are 

 found to harmonize with the surroundings. This is sufficiently 

 shown by the fact that hardly two are coloured alike, even out of 

 the same brood. I have also not remarked any seasonal changes 

 of colour in this species (after desquamation the hues are 

 naturally more vivid) ; nor are there any pronounced sexual 

 differences in colour, though some shades are more common to 

 one sex. 



Its varieties are unlimited, and have given rise to a great 

 deal of confusion — witness many Italian herpetological works — 

 between this species and V. aspis. There is much analogous, or 

 parallel, colour variation between these two species, which are 

 further structurally so bound together by a series of intermediate 

 types that, according to some of the best authorities, no distinct 

 line of demarcation can be drawn between them. 



I am not aware that the red Coluber chersea, L., occurs in the 

 Grand Duchy, but it does in other parts of Southern Germany, 

 and I was interested to notice that it is accredited here, as in 

 parts of England, with greater irritability than the other forms. 

 It is noticeable that this colour is supposed, in other creatures 

 also, to indicate the same temperament. 



The black variety has been held to be peculiar to the female 

 sex, probably because these exceed the males in numbers, and 

 are less agile in escaping detection. It is found sporadically 

 throughout the whole range of V. berus, but certainly in greatest 

 abundance (though not exclusively), for some unexplained reason, 

 in mountainous districts. I have caught one or two of the 

 ordinary typo above 8000 ft. elevation. This form has been 

 known to produce young of the normal colour. 





