﻿Arthur. 
  — 
  On 
  the 
  Brown 
  Trout 
  introduced 
  into 
  Oiago. 
  281 
  

  

  and 
  water 
  cTuriiag 
  each 
  day 
  of 
  tlie 
  fishing 
  season, 
  it 
  was 
  found 
  that 
  most 
  

   sahnon 
  were 
  killed 
  with 
  the 
  rod 
  on 
  Loch 
  Tay 
  when 
  the 
  difference 
  in 
  tem- 
  

   perature 
  did 
  not 
  exceed 
  2° 
  Fah, 
  ; 
  but 
  when 
  it 
  became 
  as 
  much 
  as 
  5°, 
  the 
  

   fish 
  ceased 
  to 
  take 
  altogether. 
  Although 
  fish 
  are 
  cold-blooded 
  animals, 
  

   this 
  would 
  appear 
  to 
  indicate 
  a 
  certain 
  degree 
  of 
  sensitiveness 
  to 
  variations 
  

   in 
  temperature. 
  It 
  is 
  not 
  so 
  easy 
  to 
  account 
  for 
  trout 
  and 
  other 
  species 
  of 
  

   the 
  Salmonidse 
  being 
  aware 
  (to 
  use 
  a 
  common 
  expression) 
  when 
  the 
  baro- 
  

   meter 
  is 
  falling 
  before 
  rain, 
  as 
  I 
  have 
  stated 
  already. 
  But 
  one 
  thing 
  I 
  am 
  

   convinced 
  of 
  is 
  that 
  they 
  do 
  feel 
  when 
  the 
  atmospheric 
  pressure 
  on 
  the 
  

   water 
  alters 
  to 
  an 
  appreciable 
  extent. 
  They 
  get 
  sluggish, 
  and 
  will 
  not 
  

   move 
  to 
  feed 
  when 
  the 
  air 
  becomes 
  rarefied. 
  But 
  when 
  the 
  weather 
  begins 
  

   to 
  change 
  and 
  clear 
  up 
  they 
  soon 
  move 
  about 
  again 
  and 
  resume 
  feeding. 
  I 
  

   explain 
  this 
  on 
  the 
  supposition 
  that, 
  in 
  the 
  first 
  instance, 
  the 
  fish 
  feel 
  their 
  

   bodies 
  sensibly 
  heavier, 
  so 
  as 
  to 
  indispose 
  them 
  to 
  move 
  ; 
  but 
  when 
  the 
  

   atmosphere 
  regains 
  its 
  normal 
  pressure, 
  they 
  are 
  relieved 
  from 
  th^sensation 
  

   of 
  weight, 
  and 
  their 
  ordinary 
  lively 
  habits 
  are 
  resumed. 
  Other 
  animals 
  — 
  

   human 
  beings 
  included 
  — 
  are 
  aifected 
  by 
  the 
  very 
  same 
  cause. 
  This 
  is, 
  no 
  

   doubt, 
  rather 
  a 
  speculative 
  part 
  of 
  my 
  subject, 
  and 
  I 
  could 
  easily 
  enlarge 
  

   my 
  remarks 
  on 
  it, 
  but 
  probably 
  I 
  have 
  said 
  enough 
  for 
  the 
  present. 
  

  

  4. 
  Distinguishing 
  Marks 
  of 
  Trout, 
  

   This 
  brings 
  me 
  to 
  the 
  concluding 
  and 
  more 
  technical 
  portion 
  of 
  my 
  paper, 
  

   but 
  before 
  going 
  into 
  that 
  I 
  think 
  it 
  will 
  be 
  better 
  to 
  record 
  my 
  examina- 
  

   tions 
  of 
  a 
  number 
  of 
  specimens 
  of 
  S. 
  fario, 
  which 
  were 
  caught 
  in 
  some 
  of 
  

   those 
  rivers 
  which 
  I 
  have 
  already 
  frequently 
  referred 
  to. 
  From 
  various 
  

   causes 
  my 
  notes 
  are 
  not 
  so 
  complete 
  as 
  they 
  should 
  be, 
  but 
  still 
  I 
  give 
  them 
  

   just 
  as 
  they 
  are. 
  They 
  may 
  be 
  useful 
  for 
  comparison 
  and 
  reference. 
  

  

  Specimens 
  of 
  Salmo 
  fario 
  examined 
  in 
  Otago, 
  

   a, 
  — 
  1877, 
  Nov. 
  30th. 
  — 
  Male 
  trout 
  caught 
  in 
  Lee 
  Stream— 
  the 
  gorge 
  

   water 
  — 
  with 
  grasshopper, 
  the 
  river 
  being 
  very 
  low. 
  Condition 
  thin, 
  head 
  

   long, 
  and 
  lower 
  jaw 
  hooked 
  ; 
  colour, 
  brown 
  on 
  back, 
  golden 
  on 
  sides, 
  

   numerous 
  black 
  spots 
  and 
  large 
  red 
  ones, 
  a 
  few 
  being 
  beneath 
  the 
  lateral 
  

   line. 
  

  

  Dimensions 
  : 
  Weight, 
  5lbs. 
  ; 
  length, 
  25 
  in. 
  ; 
  depth, 
  6 
  in. 
  ; 
  head, 
  6J 
  in. 
  ; 
  

   maxillary 
  bone 
  projecting 
  \ 
  in. 
  behind 
  the 
  vertical 
  from 
  posterior 
  margin 
  

   of 
  orbit; 
  sixteen 
  round 
  black 
  spots 
  on 
  gill-cover, 
  one 
  side. 
  Teeth, 
  vomer 
  

   three 
  firm 
  five 
  loose, 
  palatines 
  each 
  well 
  armed 
  with 
  teeth, 
  tongue 
  also, 
  and 
  

   with 
  two 
  small 
  teeth 
  loose 
  near 
  the 
  tip. 
  

  

  Fin 
  B,ays 
  : 
  P. 
  14 
  on 
  each 
  fin; 
  C.21 
  (doubtful). 
  Scales: 
  16 
  in 
  trans- 
  

   verse 
  row 
  from 
  adipose 
  fin 
  backwards 
  to 
  lateral 
  line. 
  Pyl. 
  caeca 
  : 
  54. 
  

   Contents 
  of 
  stomach 
  : 
  crayfish, 
  2 
  in. 
  long, 
  and 
  remains 
  of 
  larger 
  one 
  ; 
  three 
  

   legs 
  of 
  a 
  grasshopper 
  and 
  part 
  of 
  a 
  black 
  beetle, 
  

  

  