1902 Reptile Studies 267 



an illustration of the gullet artificially distended with air, 

 which gives some idea of its dimensions ; but it was not 

 until August of this year that I obtained a specimen which 

 was just what I wanted. Curiously enough, this came at 

 the very time when considerable discussion was going on in 

 the press on this precise point. When captured, it was 

 obvious that there was some bulky material in the throat 

 region, and this gave the adder a very distorted appearance. 

 Fortunately I was able to dissect the reptile almost at once, 

 and preserve it just as opened. Immediately afterwards I 

 had the specimen photographed, and the result is reproduced 

 on the next page. 



The dissection simply consisted in fixing the adder down 

 on a wooden dish on its back, and making a median in- 

 cision along the belly over the region of the bulky contents. 

 The two sides of the body wall were then turned outwards 

 and fixed, thus exposing the gullet or oesophagus along its 

 whole length. The state of affairs was quite evident with- 

 out any further procedure, owing to the thinness of the 

 gullet, which was tightly stretched over the mass inside. 

 Unless one saw a specimen such as this, it would tax the 

 credulity to believe how the gullet can be stretched without 

 rupture. In order to display the contents still more dis- 

 tinctly, I made a longitudinal incision through the thin- 

 walled gullet over the region of the head of the animal 

 inside, and another incision over the region of the hind- 

 legs. Thus clearly displayed, there was no difficulty in 

 recognising the contents as a large specimen of the long- 

 tailed field-mouse. The front legs of the animal were so 

 clearly visible through the gullet wall that I did not expose 

 them further. 



If my readers will now look carefully at the illustration, 

 they will, I think, be able to make out with ease the follow- 

 ing points : — 



Note first the light colour of the under-surface of the chin 

 of the adder ; the actual colour is reddish-yellow. This is a 

 sexual colouration characteristic of females. In the male the 

 scales in this region are generally black-edged or blackish 

 all over. Then observe the mottled - grey appearance of 

 the wide belly scales, also characteristic of the female, as 



