96 THE SNAKES OF SOUTH AFRICA. 



immediately despatched for the District Surgeon. Fortunately, 

 the snake was not of a kind whose venom acts promptly, for the 

 messenger had to ride four miles, and the doctor four miles 

 ere medical assistance could be rendered to the sufferer. 

 Dr. Wildish took wdth him the anti-venom discovery of the 

 Pasteur Institute, and its effects have so far been successful." 

 Subsequently, water was poured down the hole where the snake 

 was seen to disappear, and behold ! out crawled a half-drowned, 

 harmless Brown House Snake. 



Three-Cornered or File Snakes. 



These snakes, although found in most parts of South Africa, 

 seem to be rather rare every\vhere. Although large and formid- 

 able-looking, the}^ are perfectly harmless. Their average length 

 is three to five feet. They are not easily mistaken for any other 

 genus of snake owing to their peculiar vertebral scales and 

 triangular-shaped body which has given rise to the name. The 

 row of scales along the backbone are bicarinate, wliich means 

 double-keeled. These scales have a groove longitudinally down 

 the centre. The colour of the middle part of these scales is 

 white, forming a long line from the head to the tail of the snake. 

 These backbone scales are rounded and larger than those on the 

 rest of the body. The colour of the upper parts is blackish 

 brown. The edges of the abdominal shields are blotched with 

 black, and the two last rows of scales on the sides are tipped 

 with white. Upper lip and abdomen white. Two species are 

 officially recognized in South Africa, viz. Simocephalus cnpensis 

 and Simocephalus nyasscB. The reason for separating them into 

 two species was because S. capensis was supposed to have two 

 postocular shields and 203-241 ventrals, and S. nyassce only a 

 single postocular and 171-185 ventrals. However, I am not 

 convinced that this difference is constant. I have examined 

 several specimens and find that the above characters which 

 are supposed to distinguish them, were not constant. In some 

 there were two postocular shields and 170 to 180 ventrals. In 

 others a single postocular and 203 to 240 ventrals, thus show- 

 ing|that these characters cannot be relied upon. I have found 

 the same thing to hold good with other species of snakes. 

 This frequent creation of new species in Zoolog}^ is being carried 



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