﻿BIVEBS 
  AS 
  FACTORS 
  IN 
  ANIMAL 
  DISTRIBUTION. 
  131 
  

  

  (Pithecia) 
  found 
  on 
  either 
  side 
  of 
  the 
  Amazon 
  Kiver, 
  whose 
  range 
  

   either 
  southward 
  or 
  northward 
  appears 
  to 
  be 
  limited 
  by 
  that 
  

   stream. 
  The 
  same 
  authority 
  instances 
  among 
  birds 
  species 
  of 
  

   Jacamar 
  (Galbula) 
  and 
  Trumpeter 
  (Psophia), 
  which 
  exhibit 
  a 
  

   similar 
  limitation, 
  particularly 
  the 
  latter, 
  where 
  five 
  distinct 
  

   species 
  are 
  relegated 
  to 
  as 
  many 
  distinct, 
  but 
  contiguous, 
  geo- 
  

   graphical 
  areas, 
  separated 
  from 
  each 
  other 
  by 
  the 
  Amazon 
  and 
  

   some 
  of 
  its 
  tributaries 
  (Negro, 
  Madeira, 
  Tocantins). 
  Of 
  about 
  

   twelve 
  species 
  of 
  Armadillo 
  (separated 
  by 
  some 
  naturalists 
  into 
  

   several 
  distinct 
  genera), 
  most 
  of 
  which 
  are 
  inhabitants 
  of 
  Brazil, 
  

   it 
  would 
  seem 
  that 
  not 
  a 
  single 
  species 
  is 
  common 
  to 
  Brazil 
  and 
  

   the 
  Argentine 
  Bepublic, 
  or 
  the 
  Argentine 
  Bepublic 
  and 
  Paraguay, 
  

   the 
  Parana 
  River, 
  with 
  its 
  tributaries, 
  evidently 
  forming 
  an 
  

   insurmountable 
  barrier 
  to 
  the 
  passage 
  of 
  this 
  animal.* 
  The 
  

   Uruguay 
  River 
  appears 
  to 
  limit 
  in 
  the 
  same 
  manner 
  the 
  east- 
  

   ward 
  progression 
  of 
  the 
  Viscacha 
  (Lagostomys 
  trichodactylus) 
  , 
  an 
  

   animal 
  allied 
  to 
  the 
  Chinchilla, 
  although, 
  as 
  has 
  been 
  pointed 
  

   out 
  by 
  Darwin, 
  the 
  trans-Uruguayan 
  plains 
  are 
  fully 
  as 
  well 
  

   adapted 
  to 
  the 
  animal 
  as 
  those 
  of 
  its 
  native 
  home.f 
  The 
  Galli- 
  

   nazo, 
  a 
  South 
  American 
  Vulture 
  (Cathartes 
  atratus), 
  is 
  stated 
  by 
  

   Darwin 
  as 
  never 
  found 
  south 
  of 
  lat. 
  41°, 
  | 
  or 
  the 
  Bio 
  Negro. 
  

  

  We 
  often 
  find 
  considerable 
  ethnographical 
  differences 
  when 
  a 
  

   great 
  river 
  has 
  been 
  crossed. 
  According 
  to 
  Keller 
  : 
  "It 
  is 
  a 
  

   remarkable 
  fact 
  that 
  the 
  Indians 
  on 
  the 
  right 
  shore 
  of 
  the 
  

   Amazon 
  neither 
  prepare 
  nor 
  use 
  the 
  poison 
  (urary 
  or 
  curare 
  — 
  

   arrow-poison), 
  though 
  the 
  plants 
  that 
  supply 
  the 
  chief 
  in- 
  

   gredients 
  are 
  certainly 
  found 
  there 
  as 
  well 
  as 
  on 
  the 
  left 
  shore, 
  

   on 
  which 
  tribes 
  differing 
  widely 
  in 
  custom 
  and 
  language 
  use 
  the 
  

   subtle 
  weapon. 
  "§ 
  According 
  to 
  Waterton, 
  " 
  the 
  wourali-poison 
  

   is 
  used 
  by 
  all 
  the 
  South 
  American 
  savages 
  betwixt 
  the 
  Amazons 
  

   and 
  the 
  Orinoco." 
  || 
  We 
  receive 
  a 
  hint 
  as 
  to 
  how 
  rivers 
  may 
  

  

  * 
  However, 
  as 
  Mr. 
  Lydekker 
  remarks, 
  Armadillos 
  " 
  are 
  said 
  to 
  be 
  able 
  

   to 
  swim 
  well 
  and 
  swiftly 
  " 
  (' 
  Roy. 
  Nat. 
  Hist.' 
  vol. 
  iii. 
  p. 
  217). 
  

  

  f 
  Cf. 
  Heilprin 
  (' 
  Geogr. 
  and 
  Geol. 
  Distr. 
  Animals,' 
  p. 
  24). 
  

  

  I 
  ' 
  Journ. 
  Research. 
  Voy. 
  Beagle,' 
  edit. 
  1890, 
  p. 
  55. 
  

  

  § 
  ' 
  The 
  Amazon 
  and 
  Madeira 
  Rivers,' 
  p. 
  110. 
  

  

  [I 
  ' 
  Wanderings,' 
  Wood's 
  edit. 
  p. 
  126. 
  — 
  The 
  poisoned 
  arrows 
  of 
  Java 
  and 
  

   Borneo 
  are 
  deadly 
  effective, 
  while 
  those 
  of 
  the 
  Philippines 
  " 
  lose 
  their 
  effect 
  

   when 
  not 
  fresh 
  " 
  (Ratzel, 
  ' 
  Hist. 
  Mankind,' 
  vol. 
  i. 
  p. 
  416). 
  When 
  pondering 
  

   over 
  this 
  question 
  on 
  the 
  Transvaal 
  veld, 
  I 
  ventured 
  to 
  write 
  to 
  Sir 
  Clements 
  

  

  