88 OPHIDIAN EEPTILES. 



infest the country with their terrible progeny. It is for this 

 decisive reason that public exhibitions of Rattlesnakes are for- 

 bidden in France. Nevertheless, two or three may be seen in the 

 collection of the Museum of Natural History at Paris, miserably 

 installed in a chest, which is quite unworthy of this establishment. 

 The Rattlesnakes are enclosed in a double cage, and every measure 

 of precaution is taken which prudence demands. 



It is a remarkable fact that the poison is secreted after death. 

 Dr. Bell, in his " History of British Reptiles," adduces the follow- 

 ing as evidence of the facts : He was dissecting very carefully 

 and minutely the poison apparatus of a large Rattlesnake, 

 which had been dead some hours; the head had been taken 

 off immediately .after death ; yet, as Dr. Bell continued his 

 dissection, the poison continued to be secreted so fast as to require 

 to be dried up occasionally with a sponge or rag : and his belief is, 

 that there could not be less than six or eight drops of the poison. 

 It is obvious that such experiments require the utmost caution, 

 seeing that preparations are not without danger. 



[The family of the Viperidce, or true Vipers, are peculiar to the 

 Old World, inclusive of Australia, with the sole known exception 

 of one species in Peru. They have generally a robust body, 

 with non-prehensile tail ; the head broad or thick, generally 

 scaly above or incompletely shielded ; the eye of moderate size, 

 with vertical pupil, and they are at once distinguished from the 

 Crotalidce by the absence of the pit below the eye. The scales 

 are keeled except in one genus (Acanthopis). For the most part, 

 these reptiles inhabit exposed and arid situations, though perhaps 

 all of them will take to the water on occasions, as does the common 

 British Adder. 



They are divided, firstly, into those which have a depressed 

 head, rounded on the sides, and covered with acutely-keeled 

 scales. Some of these have large nostrils in the centre of a ring- 

 like shield, edged with a large scale above. Such are the genera 

 Daboia in the warmer parts of Asia, and Clotho, which is peculiar 

 to Africa both genera are terrifically venemous. 



The famous Tic-polonga of Ceylon (Daboia elegans) is also 

 widely diffused over India and Burmah. It is beautifully marked 

 with three rows of white-edged, oblong, brown spots. Occa- 



