﻿534 
  REPOKT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  [46] 
  

  

  On 
  the 
  morning 
  of 
  the 
  13th 
  of 
  July, 
  a 
  little 
  after 
  10 
  o'clock, 
  we 
  noticed 
  a 
  

   mass 
  of 
  whitish 
  eggs 
  in 
  one 
  of 
  our 
  aquaria 
  inhabited 
  by 
  three 
  adult 
  speci- 
  

   mens 
  of 
  Ictalurus 
  albidus, 
  two 
  of 
  which 
  were 
  unmistakably 
  the 
  parents 
  of 
  

   the 
  brood, 
  for 
  the 
  reason 
  that 
  they 
  did 
  not 
  permit 
  the 
  third 
  one 
  to 
  approach 
  

   near 
  the 
  mass 
  of 
  eggs 
  which 
  one 
  of 
  them 
  was 
  watching 
  vigilantly. 
  One 
  of 
  

   the 
  individuals 
  remained 
  constantly 
  over 
  the 
  eggs, 
  agitating 
  the 
  water 
  

   over 
  them 
  with 
  its 
  anal, 
  ventral, 
  and 
  pectoral 
  fins. 
  This 
  one 
  subsequently 
  

   proved 
  to 
  be 
  the 
  male 
  and 
  not 
  the 
  female, 
  as 
  was 
  at 
  first 
  supposed. 
  The 
  

   female, 
  after 
  the 
  eggs 
  were 
  laid, 
  seemed 
  to 
  take 
  no 
  further 
  interest 
  in 
  

   them, 
  the 
  whole 
  duty 
  of 
  renewing 
  and 
  forcing 
  the 
  water 
  through 
  the 
  

   mass 
  of 
  adherent 
  ova 
  devolving 
  upon 
  the 
  male, 
  who 
  was 
  most 
  assidu- 
  

   ous 
  in 
  this 
  duty 
  until 
  the 
  young 
  had 
  escaped 
  from 
  the 
  egg-membranes. 
  

   During 
  all 
  of 
  this 
  time, 
  or 
  for 
  a 
  period 
  of 
  about 
  a 
  week, 
  the 
  male 
  was 
  never 
  

   seen 
  to 
  abandon 
  his 
  post, 
  nor 
  did 
  it 
  seem 
  that 
  he 
  much 
  cared 
  even 
  after- 
  

   words 
  to 
  leave 
  the 
  scene 
  where 
  he 
  had 
  so 
  faithfully 
  labored 
  to 
  bring 
  

   forth 
  from 
  the 
  eggs 
  the 
  brood 
  left 
  in 
  his 
  charge 
  by 
  his 
  apparently 
  care- 
  

   less 
  spouse. 
  The 
  male 
  measured 
  15 
  inches 
  in 
  length, 
  the 
  female 
  a 
  fourth 
  

   of 
  an 
  inch 
  more. 
  

  

  On 
  the 
  30th 
  of 
  June, 
  or 
  when 
  the 
  young 
  were 
  seventeen 
  days 
  old, 
  it 
  

   was 
  determined 
  to 
  make 
  an 
  examination 
  of 
  the 
  internal 
  organs 
  of 
  both 
  

   parents, 
  which 
  was 
  done 
  in 
  the 
  presence 
  of 
  Professor 
  Gill, 
  to 
  learn 
  which 
  

   one 
  of 
  the 
  parent 
  fishes 
  it 
  was 
  that 
  had 
  acted 
  as 
  nurse. 
  Fortunately 
  

   there 
  was 
  considerable 
  difference 
  between 
  the 
  two 
  in 
  color 
  ; 
  the 
  female 
  

   had 
  also 
  lost 
  a 
  part 
  of 
  one 
  maxillary 
  barbel, 
  so 
  that 
  it 
  was 
  easy 
  to 
  dis- 
  

   tinguish 
  the 
  two 
  fishes 
  apart. 
  The 
  darker 
  specimen, 
  with 
  the 
  broader 
  

   head, 
  we 
  found 
  was 
  the 
  male, 
  which, 
  as 
  already 
  stated, 
  had 
  acted 
  as 
  

   the 
  nurse. 
  Upon 
  cutting 
  him 
  open 
  and 
  removing 
  a 
  portion 
  of 
  the 
  milt 
  

   or 
  testes 
  they 
  were 
  found 
  as 
  a 
  lobulated 
  pair 
  of 
  organs, 
  lying 
  one 
  on 
  

   either 
  side 
  of 
  the 
  mesentery 
  and 
  depending 
  from 
  the 
  dorsal 
  wall 
  of 
  the 
  

   abdominal 
  cavity. 
  The 
  lobes 
  of 
  the 
  testes 
  were 
  digitate. 
  Upon 
  com- 
  

   pressing 
  fragments 
  of 
  the 
  testes 
  under 
  the 
  microscope, 
  active 
  sperma- 
  

   tozoa 
  w 
  r 
  ere 
  passed 
  out. 
  The 
  spent 
  roe 
  or 
  ovary 
  of 
  the 
  female 
  was 
  a 
  

   paired 
  organ, 
  the 
  right 
  and 
  left 
  sacs 
  of 
  which 
  were 
  joined 
  together 
  pos- 
  

   teriorly. 
  The 
  ovarian 
  lobes 
  or 
  leaflets 
  were 
  disposed 
  transversely 
  in 
  

   the 
  sacs. 
  

  

  The 
  mass 
  of 
  ova 
  deposited 
  by 
  the 
  female 
  on 
  the 
  13th 
  of 
  July 
  in 
  one 
  

   corner 
  and 
  at 
  one 
  end 
  of 
  the 
  slate 
  bottom 
  of 
  the 
  aquarium 
  measured 
  

   about 
  8 
  inches 
  in 
  length 
  and 
  nearly 
  4 
  inches 
  in 
  width, 
  and 
  was 
  nowhere 
  

   much 
  over 
  one-half 
  to 
  three-fourths 
  of 
  an 
  inch 
  in 
  thickness. 
  There 
  were 
  

   probably 
  2,000 
  ova 
  in 
  the 
  whole 
  mass, 
  as 
  nearly 
  as 
  could 
  be 
  estimated. 
  

   The 
  single 
  ova 
  measured 
  about 
  one-sixth 
  of 
  an 
  inch 
  in 
  diameter 
  a 
  short 
  

   time 
  after 
  oviposition. 
  

  

  The 
  ova 
  were 
  covered 
  with 
  an 
  adhesive 
  but 
  not 
  gelatinous 
  envelope, 
  

   so 
  that 
  they 
  were 
  adherent 
  to 
  the 
  bottom 
  of 
  the 
  aquarium 
  and 
  to 
  each 
  

   other 
  where 
  their 
  spherical 
  surfaces 
  came 
  in 
  contact, 
  and 
  consequently 
  

   had 
  intervening 
  spaces 
  for 
  the 
  free 
  passage 
  of 
  water, 
  such 
  as 
  would 
  be 
  

  

  