﻿326 
  DR 
  DAVY'S 
  OBSERVATIONS 
  ON 
  THE 
  CHARR. 
  

  

  projecting, 
  resembling 
  fins, 
  and 
  were 
  in 
  constant 
  motion 
  over 
  the 
  branchial 
  arches, 
  

   in 
  which 
  the 
  blood 
  corpuscles 
  were 
  to 
  be 
  seen 
  circulating 
  in 
  looped 
  vessels. 
  

  

  On 
  the 
  4th 
  of 
  February, 
  it 
  is 
  noticed 
  that 
  the 
  fish 
  were 
  acquiring 
  colour, 
  dark 
  

   colouring 
  matter 
  being 
  deposited 
  in 
  stelliform 
  specks 
  ; 
  that 
  the 
  embryonic 
  fin 
  was 
  

   diminishing, 
  and 
  that 
  the 
  adipose 
  fin 
  was 
  beginning 
  to 
  appear, 
  marked 
  by 
  a 
  slight 
  

   elevation. 
  

  

  On 
  the 
  14th 
  of 
  the 
  same 
  month, 
  they 
  were 
  found 
  to 
  have 
  increased 
  to 
  about 
  

   •8 
  of 
  an 
  inch 
  in 
  length, 
  and 
  the 
  yolk 
  to 
  have 
  diminished 
  to 
  *2 
  of 
  an 
  inch, 
  and 
  to 
  

   have 
  become 
  narrower. 
  

  

  On 
  the 
  22d, 
  the 
  water 
  in 
  which 
  they 
  were 
  kept 
  was 
  frozen 
  over 
  : 
  they 
  were 
  

   seen 
  swimming 
  actively 
  under 
  the 
  ice, 
  and 
  restlessly, 
  as 
  if 
  in 
  search 
  of 
  a 
  passage 
  

   to 
  deeper 
  and 
  less 
  cold 
  water. 
  

  

  On 
  the 
  13th 
  of 
  March, 
  the 
  dorsal 
  fin 
  was 
  almost 
  apart, 
  the 
  other 
  fins 
  advan- 
  

   cing, 
  the 
  single 
  one 
  receding 
  from 
  absorption 
  ; 
  the 
  tail 
  still 
  rounded 
  ; 
  the 
  abdo- 
  

   minal 
  integument 
  extending 
  over 
  the 
  diminishing 
  yolk, 
  but 
  not 
  yet 
  entirely 
  

   covering 
  it. 
  

  

  One 
  died 
  on 
  the 
  18th 
  of 
  this 
  month 
  ; 
  the 
  others 
  on 
  the 
  following 
  day. 
  In 
  

   these 
  there 
  was 
  an 
  appearance 
  of 
  sooty 
  matter 
  about 
  the 
  gills, 
  which 
  probably 
  

   was 
  the 
  cause 
  of 
  their 
  death, 
  by 
  obstructing 
  respiration. 
  One 
  of 
  them, 
  weighed, 
  

   was 
  found 
  to 
  be 
  little 
  more 
  than 
  half 
  the 
  original 
  weight 
  of 
  the 
  egg 
  ; 
  merely 
  

   wiped, 
  it 
  was 
  equal 
  to 
  -58 
  of 
  a 
  grain 
  ; 
  thoroughly 
  dried, 
  at 
  a 
  temperature 
  of 
  100 
  , 
  

   it 
  was 
  reduced 
  to 
  *16 
  of 
  a 
  grain. 
  From 
  the 
  time 
  of 
  their 
  hatching 
  to 
  that 
  of 
  their 
  

   death, 
  I 
  am 
  not 
  aware 
  that 
  they 
  had 
  taken 
  any 
  food 
  other 
  than 
  that 
  provided 
  for 
  

   them 
  by 
  nature 
  in 
  the 
  attached 
  yolk, 
  a 
  period 
  of 
  sixty 
  and 
  sixty-one 
  days. 
  Pro- 
  

   bably 
  had 
  they 
  been 
  favourably 
  situated, 
  where 
  they 
  could 
  have 
  found 
  suitable 
  

   food 
  in 
  the 
  water, 
  their 
  growth 
  would 
  have 
  been 
  more 
  rapid. 
  One 
  taken 
  from 
  

   the 
  breeding-boxes 
  on 
  'the 
  22d 
  of 
  March, 
  hatched 
  about 
  the 
  same 
  time 
  as 
  the 
  

   preceding, 
  viz., 
  the 
  17th 
  of 
  January, 
  and 
  when, 
  consequently, 
  about 
  sixty-five 
  

   days 
  old, 
  may 
  be 
  adduced 
  in 
  proof; 
  premising 
  that, 
  from 
  the 
  manner 
  in 
  which 
  

   the 
  boxes 
  were 
  supplied 
  with 
  water, 
  and 
  their 
  being 
  shaded 
  with 
  trees, 
  and 
  some 
  

   aquatic 
  plants 
  having 
  been 
  introduced, 
  brought 
  from 
  the 
  bed 
  of 
  the 
  Brathay— 
  that 
  

   part 
  of 
  the 
  river 
  where 
  the 
  charr 
  is 
  known 
  to 
  spawn 
  — 
  there 
  was 
  probably 
  no 
  want 
  

   of 
  the 
  proper 
  food 
  of 
  the 
  young 
  fish, 
  minute 
  insects 
  and 
  infusorial 
  animalcules, 
  

   traces 
  of 
  which, 
  indeed, 
  were 
  detected 
  in 
  its 
  excrements, 
  when 
  seen 
  under 
  the 
  

   microscope 
  using 
  a 
  high 
  power. 
  The 
  young 
  fish 
  of 
  the 
  age 
  mentioned 
  was 
  perfect 
  

   in 
  its 
  form. 
  The 
  embryonic 
  fin 
  had 
  entirely 
  disappeared, 
  with 
  the 
  exception 
  of 
  

   a 
  slight 
  vestige 
  of 
  it 
  between 
  the 
  anal 
  and 
  the 
  abdominal 
  fins. 
  All 
  the 
  permanent 
  

   fins 
  had 
  become 
  distinct, 
  even 
  the 
  adipose, 
  though 
  it 
  was 
  rather 
  more 
  extended 
  

   and 
  less 
  elevated 
  than 
  in 
  the 
  full-grown 
  fish. 
  The 
  caudal 
  had 
  lost 
  its 
  rounded 
  

   form, 
  and 
  had 
  become 
  not 
  forked 
  but 
  square. 
  No 
  vestige 
  remained 
  externally 
  of 
  

   the 
  yolk-vesicle, 
  the 
  abdomen 
  being 
  entirely 
  closed, 
  covered 
  uniformly 
  with 
  a 
  

  

  