Poisonous Snakes of British Guiana. 405 



that therefore the number of rings give the age of the snake, 

 is quite a mistaken one. Young rattlers are observed to 

 exuviate on an average about every two months, and adults 

 at times varying from three to five months under normally 

 healthy conditions. Moreover the rings observed on a rattle 

 vary entirely according to the number of pieces which have 

 been broken away by damage from contact with sticks, stones, 

 and other such objects. The older and more delicate pieces 

 invariably get broken off, and those that remain represent 

 only the harder and denser pieces which have been added 

 during the most recent exuviations. The number present 

 therefore is purely accidental. 



As already mentioned, this is the commonest of the 

 venomous snakes in the cleared or savannah lands. They 

 will be found occasionally in cultivated fields, under or in the 

 houses of the settlements, or along the paths, and are more 

 frequently met with in open sandy and rocky ridges and 

 wastes than in the actual swamps. Open lands with low 

 scattered bushes are much more preferred than high forest, 

 where they are seldom if ever met with. 



The species is much less secluded in its habits than the 

 generality of serpents, and will be more frequently observed 

 in exposed places in the daytime than other forms, though 

 the greater part of its activity is exercised at night, as is 

 customary in the group. As a fact, much of the security of 

 man as against snake-bite is due to the nocturnal habits of 

 these creatures, owing to which they are not frequently 

 brought in contact with man in the retired places which they 

 seek out from daylight. 



Little is known of the breeding-habits of these creatures. 

 From actual cases which have been under observation, it 

 seems likely that the number of young produced at one time 

 is about from twenty to thirty — twenty-three, twenty-four, 

 and twenty-two being the numbers in three cases. 



The rattlesnake reaches a length of from 5 to 6 feet, and 

 the adult females are peculiarly stout. 



In many of its characters the bushmaster or Coonoocooshi 

 {Lachesis mutus) closely resembles the rattlesnake. The 

 ground- tint, however, is reddish or maize-coloured, while the 

 rhombs, which are elongated and irregular, are of a deep 

 chocolate or purplish black. The tail is terminated by a 

 conical spine replacing the rattle, and its under surface is 

 covered with small scales instead of the ordinary posterior 

 shields. The gape is marked by a black streak, and the 

 shield above the eye (supraocular) is small and narrow com- 

 pared with the width of the head. 



