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  ANNUAL 
  REPORT 
  SMITHSONIAN 
  INSTITUTION, 
  194 
  3 
  

  

  blue, 
  yellow, 
  or 
  brown 
  colors 
  — 
  brightest 
  after 
  the 
  skin 
  is 
  shed 
  — 
  the 
  

   rhinoceros 
  viper 
  (Bitis 
  nasicomis, 
  pi. 
  12, 
  fig. 
  1) 
  is 
  a 
  most 
  astonishing 
  

   creature. 
  One 
  would 
  expect 
  that 
  these 
  bright 
  hues 
  would 
  make 
  the 
  

   snake 
  very 
  conspicuous, 
  but 
  on 
  the 
  contrary 
  they 
  render 
  the 
  serpent 
  

   almost 
  invisible 
  in 
  the 
  swampy 
  regions 
  near 
  streams, 
  especially 
  when 
  

   its 
  rough 
  scales 
  are 
  caked 
  with 
  mud. 
  Another 
  common 
  name, 
  the 
  

   river 
  jack, 
  is 
  derived 
  from 
  its 
  partially 
  aquatic 
  habits. 
  It 
  does 
  not 
  

   seem 
  to 
  grow 
  longer 
  than 
  4 
  feet. 
  It 
  is 
  peculiarly 
  placid 
  and 
  inof- 
  

   fensive 
  in 
  disposition 
  and 
  is 
  said 
  to 
  be 
  most 
  reluctant 
  to 
  bite, 
  although 
  

   the 
  venom 
  may 
  be 
  even 
  more 
  toxic 
  than 
  that 
  of 
  the 
  following 
  species. 
  

   Its 
  food 
  habits 
  are 
  not 
  known, 
  although 
  presumably 
  from 
  its 
  aquatic 
  

   habits 
  it 
  may 
  add 
  frogs, 
  toads, 
  and 
  even 
  fishes 
  to 
  the 
  usual 
  viperine 
  

   diet 
  of 
  rodents. 
  It 
  is 
  practically 
  confined 
  to 
  the 
  rain 
  forest, 
  including 
  

   Liberia, 
  the 
  Gold 
  Coast, 
  Togo, 
  Nigeria, 
  Cameroon, 
  Portuguese 
  Guinea, 
  

   Belgian 
  Congo, 
  Uganda, 
  and 
  part 
  of 
  Kenya 
  Colony. 
  

  

  The 
  Gaboon} 
  viper. 
  

  

  This 
  malevolent-looking 
  serpent 
  (Bitis 
  gabonica, 
  pi. 
  12, 
  fig. 
  2) 
  is 
  

   very 
  highly 
  poisonous, 
  and 
  its 
  prey 
  is 
  killed 
  almost 
  instantly 
  by 
  

   injections 
  driven 
  deeply 
  with 
  the 
  long 
  fangs. 
  Its 
  venom 
  is 
  partic- 
  

   ularly 
  deadly 
  as 
  far 
  as 
  mankind 
  is 
  concerned, 
  for 
  it 
  contains 
  both 
  

   the 
  normal 
  viperine 
  haemotoxic 
  elements 
  and 
  powerful 
  neurotoxic 
  

   properties. 
  It 
  lives 
  in 
  heavy 
  forests 
  in 
  West 
  Africa. 
  It 
  is 
  known 
  

   to 
  reach 
  a 
  length 
  of 
  5 
  feet 
  8 
  inches, 
  the 
  fangs 
  of 
  such 
  a 
  monster 
  meas- 
  

   uring 
  nearly 
  2 
  inches, 
  and 
  the 
  body 
  nearly 
  15 
  inches 
  around. 
  It 
  is 
  not 
  

   usually 
  aggressive 
  and 
  has 
  the 
  habit 
  of 
  deflating 
  its 
  body 
  in 
  a 
  loud 
  

   hiss. 
  It 
  feeds 
  upon 
  small 
  mammals 
  and 
  birds, 
  toads 
  and 
  frogs. 
  There 
  

   is 
  a 
  series 
  of 
  oblong 
  buff 
  markings 
  on 
  the 
  back, 
  surrounded 
  by 
  rich 
  

   brown 
  and 
  purplish 
  spots 
  ; 
  the 
  sides 
  have 
  irregular 
  brown 
  or 
  purple 
  

   spots, 
  the 
  points 
  directed 
  upward. 
  The 
  ground 
  color 
  of 
  the 
  skin 
  is 
  

   pinkish 
  brown. 
  The 
  eyes 
  are 
  silvery. 
  Sometimes 
  there 
  is 
  a 
  blunt 
  or 
  

   forked 
  horn 
  on 
  the 
  nose. 
  

  

  The 
  horned 
  adders. 
  

  

  Two 
  of 
  these 
  small 
  snakes 
  (Bitis 
  cornuta 
  and 
  B. 
  caudalis) 
  have 
  one 
  

   or 
  more 
  hornlike 
  scales 
  over 
  the 
  eye, 
  hence 
  their 
  common 
  name. 
  

   They 
  are 
  no 
  more 
  than 
  l 
  1 
  /^ 
  feet 
  in 
  length 
  but 
  are 
  extremely 
  danger- 
  

   ous 
  in 
  spite 
  of 
  their 
  small 
  size, 
  owing 
  to 
  their 
  habit 
  of 
  burying 
  them- 
  

   selves 
  in 
  the 
  sand 
  with 
  only 
  the 
  head 
  above, 
  where 
  they 
  lie 
  for 
  hours 
  

   watching 
  for 
  lizards 
  and 
  other 
  small 
  creatures 
  on 
  which 
  they 
  feed. 
  

   They 
  bite 
  instantly 
  at 
  the 
  bare 
  feet 
  of 
  any 
  native 
  who 
  may 
  come 
  

   near 
  them, 
  for 
  they 
  are 
  practically 
  invisible 
  as 
  they 
  lie 
  hidden. 
  They 
  

   occur 
  only 
  in 
  the 
  sandy 
  areas 
  of 
  the 
  southern 
  part 
  of 
  Africa. 
  

  

  The 
  berg 
  adder 
  (B. 
  atropos) 
  as 
  its 
  name 
  indicates, 
  lives 
  upon 
  the 
  

   mountain 
  ranges 
  throughout 
  the 
  whole 
  of 
  South 
  Africa. 
  It 
  devours 
  

  

  