36 NATURAL HISTORY ESSAYS 



the bandicoots being true marsupials have no real 

 affinity with the Algerian shrew. 



The nocturnal habits of the macroscelides expose 

 it to the attacks of predaceous reptiles. A deadly 

 enemy to small mammalia — the cerastes viper — 

 haunts the African desert. This brute is about two 

 feet long, of a uniform yellow colour or else marked 

 with some thirty or forty dark brown spots. The 

 head is broad, flat, and swollen by the lateral bulging 

 of a pair of glands which secrete a poison deadly to 

 small aniraals and fatal even to man. Some cerastes 

 have a short curved horn situated above each eye ; 

 others are hornless. Dr. Anderson, who studied 

 these reptiles some years ago in Egypt, obtained both 

 horned and hornless cerastes of both sexes yet the 

 same species, so that this remarkable variation is 

 puzzling to account for. The cerastes lie almost 

 hidden in the sand, which they heap upon their 

 bodies by a lateral scooping movement; thus 

 little save the top of the head remains exposed. 

 They are also practically invisible from their 

 coloration, which harmonises with that of the sand. 

 Happily their sluggish disposition renders them 

 unwilling to bite when discovered; yet one can well 

 appreciate the cool courage of the professional snake 

 hunters, who take these deadly brutes alive by 

 pressing on the back of the neck with a cleft stick. 



A cerastes opened by Bruce contained the remains 

 of a jerboa, and those obtained by Dr. Anderson were 



