﻿[59] 
  

  

  DEVELOPMENT 
  OF 
  THE 
  CETACEA. 
  485 
  

  

  Fig. 
  15. 
  Diagrammatic 
  figure 
  illustrating 
  six 
  stages 
  of 
  the 
  outgrowth 
  of 
  the 
  flukes 
  

   of 
  cetaceans, 
  the 
  successive 
  contours 
  being 
  compiled 
  from 
  various 
  sources 
  ; 
  the 
  last 
  

   stage 
  being 
  approximately 
  that 
  of 
  the 
  flukes 
  of 
  the 
  adult 
  to 
  show 
  the 
  way 
  in 
  which 
  

   the 
  caudal 
  notch 
  is 
  developed 
  over 
  the 
  end 
  of 
  the 
  tail. 
  

  

  Fig. 
  16. 
  View 
  of 
  the 
  top 
  of 
  the 
  head 
  of 
  a 
  foetus 
  of 
  Megaptera 
  longimana, 
  natural 
  size, 
  

   to 
  show 
  the 
  arrangement 
  of 
  the 
  hair 
  follicles 
  or 
  vibrissas 
  on 
  the 
  snout. 
  After 
  Es- 
  

   chricht. 
  

  

  Fig. 
  17. 
  View 
  of 
  right 
  flipper 
  or 
  fore 
  limb 
  of 
  the 
  foetus 
  of 
  Globiocephalus 
  represented 
  

   in 
  Fig. 
  9, 
  Plate 
  I 
  ; 
  drawn 
  after 
  the 
  whole 
  limb 
  was 
  detached 
  and 
  rendered 
  transparent 
  

   with 
  clove 
  oil. 
  Enlarged 
  16 
  times, 
  h 
  humerus, 
  r 
  radius, 
  u 
  ulna, 
  p 
  pisiforme, 
  I 
  pollex, 
  

   and 
  II, 
  III, 
  IV, 
  and 
  V, 
  digits. 
  

  

  EXPLANATION 
  OF 
  PLATE 
  III. 
  

  

  Fig. 
  18. 
  Head 
  of 
  male 
  foetus 
  of 
  Balcenoptera 
  rostrata, 
  natural 
  size, 
  showing 
  the 
  two 
  

   blow-holes 
  and 
  three 
  follicles 
  on 
  either 
  edge 
  of 
  the 
  snout 
  for 
  vibrissas. 
  After 
  Es- 
  

   chricht. 
  

  

  Fig, 
  19. 
  Side 
  view 
  of 
  the 
  same 
  foetus 
  displaying 
  four 
  follicles 
  for 
  vibrissas 
  below 
  the 
  

   edge 
  of 
  the 
  lower 
  lip, 
  and 
  showing 
  the 
  median 
  notch 
  at 
  the 
  end 
  of 
  the 
  tail. 
  After 
  

   Eschricht. 
  

  

  Fig. 
  20. 
  The 
  inner 
  contour 
  lines 
  show 
  the 
  form 
  of 
  the 
  tail 
  of 
  a 
  foetal 
  manatee, 
  nat- 
  

   ural 
  size, 
  from 
  below, 
  with 
  a 
  median 
  papilla 
  near 
  the 
  end 
  and 
  within 
  the 
  lower 
  mar- 
  

   gin, 
  a 
  anus, 
  cl. 
  clitoris. 
  After 
  Wilder. 
  

  

  The 
  outer 
  contour 
  shows 
  the 
  configuration 
  of 
  the 
  tail 
  of 
  a 
  young 
  male 
  manatee 
  4 
  

   feet 
  long, 
  as 
  seen 
  from 
  above, 
  and 
  reduced 
  from 
  Murie's 
  figure 
  to 
  nearly 
  one-fifteenth 
  

   natural 
  size 
  in 
  order 
  to 
  show 
  the 
  changes 
  of 
  form 
  undergone 
  by 
  the 
  tail 
  in 
  passing 
  

   from 
  the 
  foetal 
  to 
  the 
  adult 
  condition. 
  

  

  Fig. 
  21. 
  Female 
  foetus 
  of 
  manatee, 
  3.7 
  inches 
  long, 
  obtained 
  by 
  the 
  late 
  Professor 
  

   Orton, 
  and 
  figured 
  by 
  Wilder. 
  Natural 
  size, 
  viewed 
  from 
  the 
  side, 
  a 
  point 
  of 
  elbow, 
  

   c 
  carpus, 
  n 
  nostril, 
  e 
  ear. 
  After 
  Wilder. 
  

  

  Fig. 
  22. 
  Male 
  foetus 
  (?) 
  of 
  Halicore 
  dugong, 
  one-half 
  natural 
  size, 
  n 
  nostril, 
  e 
  ear, 
  u 
  

   umbilical 
  cord, 
  p 
  penis 
  (?), 
  a 
  anus. 
  After 
  Harting. 
  

  

  