﻿184 
  THE 
  ZOOLOGIST. 
  

  

  injury, 
  as 
  the 
  pulp 
  of 
  the 
  fruit 
  is 
  exceedingly 
  oily. 
  " 
  This 
  is 
  an 
  

   example 
  of 
  modification 
  for 
  dissemination 
  by 
  water."* 
  

  

  Even 
  rivers 
  influence 
  the 
  route 
  of 
  bird 
  migration. 
  Prof. 
  

   Mosso, 
  from 
  an 
  examination 
  of 
  a 
  map 
  illustrating 
  Palmen's 
  law 
  

   of 
  bird 
  migration, 
  states 
  " 
  that 
  the 
  birds 
  follow 
  by 
  preference 
  the 
  

   great 
  river 
  valleys 
  and 
  the 
  shores 
  of 
  sea 
  and 
  ocean. 
  One 
  of 
  the 
  

   most 
  frequented 
  routes 
  in 
  Europe 
  is 
  the 
  valley 
  of 
  the 
  Rhine 
  as 
  

   far 
  as 
  Switzerland. 
  It 
  is 
  round 
  the 
  Swiss 
  lakes, 
  indeed, 
  that 
  the 
  

   greater 
  number 
  of 
  northern 
  birds 
  are 
  found. 
  To 
  go 
  to 
  Africa, 
  

   they 
  pass 
  the 
  Lake 
  of 
  Geneva 
  and 
  the 
  Mediterranean 
  by 
  the 
  

   valley 
  of 
  the 
  Ehone. 
  Here 
  the 
  route 
  divides, 
  and 
  the 
  birds 
  

   reach 
  their 
  destination 
  by 
  either 
  the 
  Italian 
  or 
  the 
  Spanish 
  

   coast-line. 
  "t 
  

  

  Part 
  III. 
  — 
  Rivers 
  Swam 
  by 
  Land 
  Animals. 
  

  

  But 
  though 
  rivers 
  may 
  at 
  the 
  present 
  time 
  — 
  and 
  undoubtedly 
  

   did 
  in 
  the 
  past 
  — 
  prove 
  a 
  barrier 
  to 
  animal 
  distribution, 
  and 
  

   especially 
  to 
  that 
  of 
  mammals, 
  still, 
  as 
  might 
  be 
  expected, 
  many 
  

   mammals 
  and 
  other 
  animals, 
  including 
  some 
  of 
  the 
  least 
  

   suspected, 
  have 
  from 
  time 
  to 
  time 
  been 
  observed 
  to 
  cross 
  wide 
  

   and 
  swift 
  rivers, 
  and 
  have 
  moreover 
  apparently 
  inherited 
  a 
  

   tendency 
  to 
  do 
  so, 
  which 
  has 
  subsequently 
  developed 
  into 
  a 
  

   somewhat 
  fixed 
  habit. 
  As 
  an 
  example, 
  the 
  Tiger 
  may 
  be 
  ad- 
  

   duced 
  as 
  an 
  animal 
  not 
  only 
  known 
  to 
  cross 
  rivers, 
  but 
  even 
  to 
  

   swim 
  across 
  an 
  arm 
  of 
  the 
  sea, 
  as 
  the 
  Singapore 
  Strait, 
  which 
  is 
  

   more 
  than 
  a 
  mile 
  in 
  width. 
  According 
  to 
  Mr. 
  Ridley, 
  "they 
  

   habitually 
  swim 
  over 
  to 
  Singapore, 
  across 
  the 
  Johore 
  Strait, 
  

   usually 
  by 
  way 
  of 
  the 
  intermediate 
  islands 
  of 
  Pulau 
  Ubin 
  and 
  

   P. 
  Tekong. 
  They 
  make 
  the 
  passage 
  at 
  night, 
  landing 
  in 
  the 
  

   early 
  morning. 
  As 
  so 
  much 
  of 
  the 
  coast 
  is 
  mangrove 
  swamp, 
  

   and 
  the 
  animals 
  do 
  not 
  risk 
  going 
  through 
  the 
  mud, 
  they 
  are 
  

   only 
  able 
  to 
  cross 
  where 
  the 
  shores 
  are 
  sandy, 
  and 
  thus 
  they 
  

  

  ;: 
  H. 
  N. 
  Ridle}-, 
  ' 
  Nat. 
  Science,' 
  vol. 
  viii. 
  p. 
  188 
  

   ■\ 
  ' 
  Fatigue,' 
  pp. 
  22-3. 
  

  

  