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THE SNAKES OF SOUTH AFRICA. 



The young Puff Adders average seven inches in length at 

 birth. They are venomous as soon as born, and will strike fiercely 

 if irritated. Mice bitten by them died within a few minutes. I 

 have made them bite full-grown rats, which died in half an hour. 

 A friend was bitten on the hand by a young Puff Adder a day or 

 two old. His arm swelled, and there was a good deal of con- 

 stitutional disturbance, but he recovered in a few days. 



During April of 1910, five Puff Adders gave birth to young in 

 the Port Elizabeth Museum. Three of the Adders brought forth 

 the whole of the young alive. The other two gave birth to many 

 fully-developed ones, as well as about a dozen only two-thirds 



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l-ic. 90. — (i) Tlie egg of a Puff Adder. These eggs develop inside the snake, and lie in two long rows. They 

 incubate within the body of the parent. (2) A young I'uff Adder just born, but only partly developed. 

 In the front is seen sonic of the egg still unabsorbed. The embryo is enveloped in a membraneous 

 bag. (3) A young I'uff Adder, fully developed, just born. It is struggling out of the transparent 

 nienibraneous sheath in which it was born. Its head is protruding. (4) A young Puff .Adder, half an 

 hour after birth, 7J inches long. One hour after birth it bit a rat. The rat was dead ia fifteen 

 minutes. They do not take food until the skin is shed, which takes place soon after birth. 



matured. I have frequently noticed on dissecting Puff Adders 

 that the young are not alwa3's developed to the same degree. 

 Sometimes the eggs fail to incubate. In this case they harden, 

 and are sometimes passed out. In other cases they remain in 

 the snake, and their presence eventually kills her. 



Puff Adders have given birth to young a great many times 

 in our snake cages at the old Port Elizabeth Museum during the 

 months of March, April, and May. This would lead us to conclude 

 that the development of theeggsandincubationperiod within the 

 mother is about seven months, as the Puff Adders begin coming 

 forth from their winter retreats mostly during September and 



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