Reptiles. 1031 



a considerable quantity (so says my note made at the time) of excre- 

 ment was found in the anal canal. I found also five pairs of rudi- 

 mental fangs, graduating from the length of those in use down to mere 

 points, floating, at least four of the five pairs, apparently unattached 

 in the venom-sac. Most specimens I have examined have had some 

 spare fangs ; but I never saw so many as in my prisoner. 



It is, I believe, thought by some, that pressure on the venom-sac, 

 when the fang has entered its whole length into the object struck, 

 propels the venom through the hollow of the fang into the wound. 

 Professor Bell says, " When the animal inflicts the wound, the pres- 

 sure on the tooth forces a small drop of the poison through the tube." 

 I do not feel sure this would cause the venom to flow. The former 

 opinion is certainly incorrect: for when the fangs of the viper alluded 

 to above, in striking at my face, came in contact with the glass be- 

 tween us, venom was invariably deposited on the glass. I am dis- 

 posed to think that the poison is propelled from the sac by sudden 

 muscular contraction. 



I am puzzled respecting the time at which the viper feeds. The 

 form of the eye would mark it as a night- feeder ; and yet I have never 

 heard of a viper's being found on the move at night : neither have 

 those I have kept in confinement evinced any increase of activity after 

 night-fall. 1 have never detected a viper on the move in the day- 

 time as if in search of food. Mr. Slater's very interesting paper (Zool. 

 829) is not conclusive on this point. Does it not watch for its prey ? 

 And is it not frequently so watching, when thought to be only bask- 

 ing? Mr. Waterton's high authority bears upon this point. "Snakes," 

 says he, "are always in a quiescent state just before they seize their 

 prey ; and their mode of capturing it is by an instantaneous spring, 

 consisting of a bound which never exceeds two-thirds of the length 

 of the reptile's body." This I suspect to be no less true of the Eng- 

 lish viper than it is of the snakes of South America. I have frequent- 

 ly found the viper coiled up, as if prepared to strike ; and it is some- 

 times much more than at others on the alert when disturbed. I find 

 it sometimes in the sunshine, and sometimes in the shade; sometimes 

 the ribs are expanded, but not so frequently, I think, as otherwise. 

 On the whole I incline to the opinion that the viper watches for, and 

 springs upon, its unsuspecting prey in the day-time. 



I think the viper brings forth during all the summer months. I 

 have caught young vipers not six inches long in the month of May ; 

 and August 12, 1841, I squeezed six young ones out of a large female. 

 I have caught vipers of all sizes, and of all colours, the summer 



