136 



NOTES TO THE 



parts-grown common mouse. It seems hardly possible that the 

 mouse could ever have gone down. 



The engraving on the preceding page represents the skin of a 

 viper. Directly the animal is killed, the skin or a portion of it 

 should be stretched on a flat glass. The beautiful pattern of the 

 scales in a skin so treated is much to be admired. Oil-cloth 

 manufacturers should copy it. 



POISON TANGS OF VIPER, p. 205. Gilbert White does not seem 

 to have been much of an anatomist. He probably therefore never 

 dissected the poison apparatus of the viper or other venomous 

 snakes. Mr. Delamotte has therefore kindly at my request 

 given us drawings of dissections I have myself made of the 

 poison apparatus of the rattlesnake. It is the same, on a 

 larger scale, as the viper. Fig. 1 represents the palate of the 



FIG. 1. PALATE AND POISON FANGS OF THE KATTLESNAKK. 



.snake ; the lower jaw is supposed to be removed altogether. The 

 poison fangs, when the snake is not irritated, lie back parallel 

 to the roof of the mouth, so that they will not at all interfere 

 when the snake is swallowing its food. On the left hand of the 

 drawing will be seen the projecting tips of the fangs. The fangs 

 lie in, and are protected by a fold of the gum, which serves two 

 purposes ; first of all, it prevents the poison being thrown broad- 

 cast when the snake bites, and secondly, it protects the fangs 

 from injury. On the right hand side are seen the fangs from 

 which the bag has been dissected off with the scissors. In this 

 case there are three poison fangs all about the same size. 



Fig. 2 shows a further dissection of the fangs as contained in 

 this pouch or bag. One side of the bag being cut away, it will 



