﻿566 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  [78] 
  

  

  EXPLANATION 
  OF 
  PLATE 
  XL 
  

  

  Ch-ETODIPTF.rus 
  faber. 
  (The 
  Moonfish.) 
  

  

  Fig. 
  57. 
  Blastodisk 
  of 
  an 
  unimpregnated 
  egg, 
  viewed 
  from 
  the 
  side. 
  

  

  Fig. 
  58. 
  Mature 
  egg, 
  showing 
  the 
  position 
  of 
  the 
  oil-drop, 
  and 
  with 
  the 
  blastodisk 
  

  

  formed. 
  

   Fig. 
  59. 
  Blastodisk, 
  with 
  about 
  3*2 
  cells, 
  viewed 
  from 
  above, 
  and 
  showing 
  the 
  subquad- 
  

  

  rate 
  form 
  usually 
  assumed 
  at 
  this 
  stage. 
  

   Fig. 
  60. 
  Entire 
  egg, 
  with 
  the 
  blastodisk 
  developed 
  to 
  about 
  the 
  condition 
  represented 
  

  

  in 
  the 
  preceding 
  figure. 
  

   Fig. 
  61. 
  The 
  blastodisk 
  of 
  Chcetodipterus 
  more 
  advanced 
  in 
  development, 
  with 
  the 
  large 
  

  

  marginal, 
  flattened 
  cells 
  very 
  apparent. 
  

   Fig. 
  62. 
  An 
  egg 
  in 
  which 
  the 
  embryo 
  is 
  apparent, 
  the 
  oil-drop 
  covered 
  by 
  periblast 
  

  

  cells, 
  pigment 
  cells 
  developed, 
  and 
  Kupffer's 
  vesicle 
  formed. 
  

   Fig. 
  63. 
  An 
  embryo 
  sixteen 
  hours 
  after 
  hatching, 
  showing 
  the 
  increased 
  capacity 
  of 
  

  

  the 
  cleavage 
  space 
  sc, 
  due 
  to 
  the 
  rapid 
  absorption 
  of 
  the 
  yelk 
  ; 
  the 
  pigment 
  cells 
  

  

  aggregated 
  at 
  definite 
  points. 
  

  

  