198 BRITISH SERPENTS. 



had stated. Of course this was not sufficient basis 

 for a final conclusion, but it was sufficient to show 

 that I was dealing with a locality in which the adder 

 was the most common serpent found, and that it did 

 attain a very large size here. The sixth adder in the 

 list was a very young male, and evidently not mature. 

 The female of 28J inches, taken within a few hundred 

 yards of my own doors, is the largest adder I have 

 ever captured, and one of the largest I can obtain 

 authentic measurements of in any district. Since 



1897 I have measured a large number of adders 

 taken in this part of the Monnow Valley, and of 

 the whole series (over a hundred specimens) I find 

 that — 



The adult male averages 24 inches, 

 it . female n 25 J n 



If these figures are compared with the averages given 

 under the heads of the various counties, it will be 

 found that the adder in the Monnow Valley attains its 

 maximum length for these isles. 



Are there, then, no other snakes in this valley but 

 adders ? The gamekeepers, farmers, and others all 

 told me that no other species was to be found, which 

 of course meant that they had seen no other kind, and 

 for two and a half years I. never saw any other serpent 

 here but the adder. Then on the 26th September 



1898 I saw the small specimen of Tropidonotus natrix 

 referred to in the chapter on that species, where the 



