﻿324 
  DR 
  DAVY'S 
  OBSERVATIONS 
  ON 
  THE 
  CHARR. 
  

  

  nating 
  the 
  ova 
  after 
  they 
  have 
  lost 
  their 
  power 
  of 
  spontaneous 
  motion, 
  I 
  cannot 
  

   offer 
  any 
  decided 
  opinion 
  ; 
  from 
  the 
  few 
  trials 
  I 
  have 
  made, 
  I 
  am 
  led 
  to 
  believe 
  

   that 
  the 
  one 
  quality 
  or 
  power 
  is 
  distinctive 
  of 
  the 
  other, 
  and 
  that, 
  ceasing 
  to 
  move, 
  

   they 
  become 
  inert. 
  

  

  In 
  a 
  charr 
  weighing 
  about 
  half 
  a 
  pound 
  I 
  have 
  found 
  the 
  number 
  of 
  ova 
  to 
  be 
  

   1230, 
  all 
  nearly 
  of 
  full 
  size. 
  As 
  the 
  volume 
  of 
  the 
  mature 
  and 
  distended 
  testes 
  

   is 
  about 
  the 
  same 
  as 
  that 
  of 
  the 
  ripe 
  ovaries, 
  the 
  number 
  of 
  spermatozoa 
  belong- 
  

   ing 
  to 
  them 
  must 
  almost 
  baffle 
  calculation 
  ; 
  and 
  if, 
  as 
  there 
  is 
  reason 
  to 
  believe, 
  

   a 
  single 
  one 
  may 
  suffice 
  to 
  impregnate 
  an 
  ovum, 
  the 
  whole 
  from 
  one 
  male 
  may, 
  it 
  

   is 
  presumed, 
  be 
  more 
  than 
  adequate 
  to 
  effect 
  the 
  impregnation 
  of 
  the 
  entire 
  eggs 
  

   of 
  many 
  females, 
  especially 
  taking 
  into 
  account 
  how 
  readily 
  these 
  minute 
  bodies 
  

   are 
  suspended 
  and 
  diffused 
  in 
  water. 
  

  

  2. 
  Of 
  the 
  time 
  required 
  for 
  the 
  hatching 
  of 
  the 
  Ova 
  ; 
  and 
  of 
  the 
  young 
  Charr 
  in 
  their 
  

  

  early 
  stage. 
  

  

  The 
  principal 
  spawning 
  season 
  of 
  the 
  charr 
  in 
  the 
  several 
  lakes 
  of 
  the 
  Lake 
  

   District 
  in 
  which 
  this 
  fish 
  occurs, 
  is 
  the 
  beginning 
  of 
  winter, 
  from 
  about 
  the 
  first 
  

   week 
  in 
  November 
  to 
  the 
  first 
  in 
  December, 
  when 
  the 
  water 
  over 
  the 
  spawning- 
  

   beds 
  has 
  become 
  comparatively 
  cool, 
  reduced 
  from 
  about 
  GO' 
  Fahr. 
  to 
  about 
  50 
  . 
  

   Whether 
  this 
  is 
  the 
  only 
  season 
  is 
  somewhat 
  doubtful 
  ; 
  the 
  fishermen 
  of 
  Winder- 
  

   mere 
  speak 
  of 
  a 
  later 
  one, 
  in 
  which 
  it 
  is 
  believed 
  by 
  them 
  that 
  fish 
  of 
  the 
  larger 
  

   size 
  and 
  few 
  in 
  number 
  deposit 
  their 
  spawn, 
  viz., 
  in 
  February 
  and 
  March.* 
  Be 
  

   this 
  as 
  it 
  may, 
  all 
  the 
  observations 
  I 
  have 
  recorded 
  were 
  made 
  on 
  spawn 
  obtained 
  

   during 
  the 
  first 
  period 
  mentioned. 
  

  

  From 
  analogy, 
  it 
  might 
  be 
  inferred 
  that 
  the 
  time 
  required 
  for 
  the 
  hatching 
  of 
  

   the 
  charr 
  would 
  be 
  a 
  variable 
  one, 
  depending 
  on 
  the 
  degree 
  of 
  temperature 
  of 
  the 
  

   water 
  and 
  on 
  other 
  less 
  appreciable 
  circumstances. 
  In 
  1850-51, 
  Mr 
  Reynolds, 
  

   as 
  he 
  informs 
  me, 
  found 
  none 
  hatched 
  in 
  a 
  shorter 
  period 
  than 
  60 
  days 
  ; 
  the 
  

   greater 
  number 
  on 
  the 
  70th, 
  and 
  from 
  that 
  to 
  the 
  75th 
  day 
  ; 
  some 
  few 
  as 
  late 
  as 
  

   the 
  90th. 
  The 
  average 
  temperature 
  of 
  the 
  water 
  in 
  the 
  breeding 
  boxes 
  was 
  about 
  

   40°. 
  At 
  a 
  higher 
  temperature, 
  viz., 
  an 
  average 
  one 
  of 
  about 
  55°, 
  I 
  have 
  wit- 
  

   nessed 
  the 
  completion 
  of 
  the 
  process 
  in 
  the 
  short 
  period 
  of 
  41 
  days. 
  In 
  this 
  in- 
  

   stance 
  the 
  milt 
  and 
  the 
  roe 
  were 
  mixed 
  as 
  soon 
  as 
  they 
  were 
  taken 
  from 
  the 
  fish 
  

   on 
  the 
  29th 
  of 
  last 
  October 
  ; 
  a 
  certain 
  number 
  of 
  the 
  ova 
  were 
  put 
  into 
  a 
  glass 
  

   vessel 
  and 
  covered 
  with 
  water 
  to 
  the 
  depth 
  of 
  about 
  an 
  inch, 
  which 
  was 
  changed 
  

   twice 
  daily, 
  and 
  kept 
  in 
  a 
  room 
  the 
  temperature 
  of 
  which 
  was 
  very 
  uniform, 
  — 
  

  

  * 
  I 
  am 
  disposed 
  to 
  think 
  that 
  the 
  breeding-time 
  of 
  the 
  charr 
  in 
  Windermere 
  is 
  even 
  less 
  limited 
  

   than 
  is 
  stated 
  above, 
  having 
  found 
  in 
  the 
  latter 
  end 
  of 
  February 
  individuals 
  -with 
  the 
  testes 
  nearly 
  of 
  

   their 
  full 
  size, 
  and 
  this 
  not 
  in 
  large 
  fish 
  ; 
  and 
  others 
  with 
  ovaries 
  containing 
  eggs 
  varying 
  in 
  size 
  

   from 
  a 
  mustard 
  to 
  a 
  millet 
  seed. 
  These 
  fish 
  were 
  all 
  from 
  the 
  lake 
  ; 
  I 
  have 
  never 
  heard 
  of 
  one 
  being 
  

   taken 
  or 
  seen 
  in 
  the 
  Brathay 
  (a 
  river 
  flowing 
  into 
  the 
  lake, 
  to 
  be 
  mentioned 
  hereafter) 
  after 
  Decem- 
  

   ber. 
  

  

  