﻿DR 
  DAVY'S 
  OBSERVATIONS 
  ON 
  THE 
  CHARR. 
  331 
  

  

  Salmonidse 
  (Coregonus 
  Palwa), 
  M. 
  Vogt 
  has 
  so 
  ably 
  and 
  elaborately 
  treated 
  of 
  in 
  

   the 
  work 
  already 
  referred 
  to. 
  

  

  The 
  observations 
  I 
  have 
  described 
  are 
  fewer 
  than 
  I 
  could 
  have 
  wished, 
  and 
  the 
  

   results 
  more 
  imperfect 
  ; 
  I 
  can 
  offer 
  them 
  only 
  in 
  the 
  manner 
  in 
  which 
  I 
  trust 
  

   they 
  will 
  be 
  received, 
  viz., 
  as 
  a 
  contribution 
  to 
  the 
  history 
  of 
  the 
  charr. 
  

  

  I 
  may 
  notice 
  some 
  of 
  the 
  facts 
  which 
  they 
  seem 
  to 
  establish, 
  and 
  some 
  of 
  the 
  

   inferences 
  which 
  they 
  appear 
  to 
  me 
  to 
  warrant. 
  

  

  1. 
  That 
  the 
  time 
  required 
  for 
  hatching 
  the 
  ova 
  of 
  the 
  charr 
  is 
  variable, 
  de- 
  

   pending 
  on 
  the 
  degree 
  of 
  temperature 
  of 
  the 
  water 
  and 
  other 
  influences 
  : 
  that 
  70 
  

   days 
  may 
  be 
  considered 
  about 
  the 
  average, 
  and 
  40 
  and 
  90 
  about 
  the 
  extremes. 
  

  

  2. 
  That 
  after 
  exclusion 
  from 
  the 
  egg 
  the 
  young 
  fish 
  can 
  live 
  at 
  least 
  60 
  days 
  

   without 
  taking 
  food, 
  deriving 
  the 
  material 
  required 
  for 
  its 
  support 
  and 
  growth 
  

   from 
  itself, 
  and 
  chiefly 
  from 
  the 
  store 
  that 
  nature 
  has 
  supplied 
  in 
  its 
  yolk. 
  

  

  3. 
  That 
  under 
  favourable 
  circumstances, 
  it 
  attains 
  its 
  perfect 
  form 
  in 
  about 
  

   from 
  60 
  to 
  70 
  days, 
  when 
  it 
  becomes 
  dependent 
  for 
  its 
  subsistence 
  chiefly 
  on 
  food 
  

   which 
  it 
  has 
  to 
  seek 
  and 
  to 
  procure 
  from 
  without 
  ; 
  though 
  even 
  then 
  it 
  is 
  pro- 
  

   bable 
  the 
  whole 
  of 
  the 
  yolk 
  is 
  not 
  expended, 
  so 
  that 
  external 
  food 
  failing, 
  the 
  

   privation 
  can 
  be 
  borne 
  and 
  life 
  maintained, 
  and 
  that 
  for 
  no 
  inconsiderable 
  time, 
  

   by 
  means 
  of 
  the 
  residual 
  yolk 
  contained 
  within 
  the 
  abdominal 
  cavity. 
  

  

  4. 
  That 
  running 
  water 
  is 
  not 
  essential 
  to 
  the 
  hatching 
  of 
  the 
  ova 
  ; 
  and, 
  in 
  

   consequence 
  of 
  its 
  breeding-place 
  being 
  distinct 
  from 
  that 
  of 
  the 
  trout, 
  it 
  is 
  exposed 
  

   to 
  little 
  risk 
  of 
  being 
  lost 
  as 
  a 
  species 
  by 
  repeated 
  crossings 
  with 
  the 
  trout. 
  

  

  5. 
  That 
  salt 
  water, 
  even 
  of 
  greater 
  saltness 
  than 
  sea-water, 
  is 
  not 
  imme- 
  

   diately 
  fatal 
  to 
  the 
  embryo, 
  even 
  when 
  not 
  included 
  in 
  its 
  shell 
  ; 
  moreover, 
  that 
  

   in 
  slightly 
  brackish 
  water 
  a 
  partial 
  development 
  of 
  the 
  ovum 
  may 
  take 
  place 
  ; 
  

   and 
  that 
  the 
  young 
  fish 
  can 
  exist 
  some 
  days 
  in 
  such 
  water, 
  rendering 
  it 
  probable 
  

   that 
  the 
  adult 
  may 
  be 
  capable 
  of 
  existing 
  in 
  a 
  tidal 
  stream, 
  or 
  even 
  in 
  the 
  sea, 
  

   for 
  a 
  time, 
  where 
  it 
  is 
  stated 
  that 
  the 
  Welsh 
  charr 
  has 
  been 
  caught.* 
  

  

  6. 
  That 
  in 
  water 
  of 
  small 
  bulk, 
  such 
  as 
  may 
  be 
  used 
  for 
  transporting 
  fish 
  

   from 
  place 
  to 
  place, 
  with 
  common 
  air, 
  the 
  young 
  charr 
  may 
  endure 
  confinement 
  

   for 
  several 
  days 
  without 
  impairment 
  of 
  its 
  vigour 
  ; 
  and 
  that 
  substituting 
  oxygen, 
  

   it 
  may 
  endure 
  such 
  confinement 
  for 
  a 
  much 
  longer 
  time, 
  at 
  least 
  quadruple 
  that 
  

   period. 
  

  

  7. 
  That 
  the 
  young 
  fish 
  can 
  bear, 
  without 
  any 
  immediate 
  injury 
  that 
  is 
  appa- 
  

   rent, 
  a 
  temperature 
  removed 
  only 
  a 
  degree 
  or 
  two 
  from 
  the 
  freezing-point 
  of 
  

   water 
  ; 
  and 
  also 
  a 
  higher 
  temperature, 
  ranging 
  from 
  60° 
  to 
  70°, 
  but 
  not 
  above 
  

   83°, 
  which, 
  in 
  the 
  single 
  instance 
  tried, 
  was 
  almost 
  instantly 
  fatal 
  to 
  it. 
  

  

  The 
  application 
  of 
  these 
  facts 
  to 
  the 
  breeding 
  and 
  transporting 
  of 
  the 
  charr 
  

  

  * 
  See 
  Mr 
  Yakrell's 
  History 
  of 
  British 
  Fishes, 
  vol. 
  ii., 
  p. 
  71. 
  1st 
  Edit, 
  

  

  