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  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  

  

  M 
  

  

  of 
  extensive 
  modifications 
  of 
  the 
  original 
  type 
  from 
  which 
  the 
  existing 
  

   cetaceans 
  have 
  descended. 
  It 
  will 
  be 
  observed 
  that 
  the 
  central 
  axis 
  of 
  

   the 
  head, 
  trunk, 
  and 
  tail 
  in 
  adult 
  cetaceans, 
  as 
  in 
  fishes, 
  are 
  continua- 
  

   tions 
  of 
  each 
  other, 
  that 
  is, 
  the 
  head 
  is 
  not 
  bent 
  downward 
  on 
  the 
  neck, 
  

   and 
  the 
  latter 
  thrown 
  upwards 
  at 
  an 
  angle 
  to 
  the 
  trunk, 
  and 
  the 
  tail 
  

   bent 
  downward 
  as 
  in 
  other 
  Mammalia; 
  that 
  this 
  was 
  not 
  the 
  original 
  

   form 
  of 
  the 
  cetacean 
  body 
  seems 
  to 
  be 
  supported 
  by 
  considerable 
  

   embryological 
  evidence. 
  

  

  (2) 
  Affinities 
  of 
  Cetaceans.— 
  Huxley, 
  with 
  his 
  usual 
  insight 
  into 
  the 
  

   probable 
  relationship 
  existing 
  between 
  living 
  forms, 
  holds 
  to 
  the 
  opinion 
  

   that 
  the 
  Phocodontia 
  (Zeuglodon, 
  &c), 
  constitute 
  the 
  connecting 
  link 
  be- 
  

   tween 
  the 
  existing 
  Cetacea 
  aud 
  the 
  aquatic 
  Camivora, 
  their 
  cervical 
  

   vertebras 
  being 
  free 
  aud 
  unanchlylosed. 
  The 
  nasal 
  bones, 
  though 
  ab- 
  

   breviated, 
  are 
  longer 
  than 
  those 
  of 
  any 
  other 
  Cetacean 
  ; 
  consequently 
  the 
  

   external 
  nareal 
  opening 
  was 
  more 
  nearly 
  terminal 
  and 
  normal 
  in 
  posi- 
  

   tion 
  than 
  in 
  existing 
  forms. 
  " 
  The 
  scapula 
  appears 
  to 
  have 
  had 
  a 
  spine 
  

   and 
  acromion 
  like 
  that 
  of 
  manatee." 
  " 
  The 
  humerus 
  is 
  compressed 
  

   from 
  the 
  side, 
  and 
  has 
  true 
  articular 
  faces 
  upon 
  its 
  distal 
  end, 
  although 
  

   they 
  are 
  of 
  small 
  size." 
  It 
  is, 
  consequently, 
  to 
  be 
  inferred 
  that 
  there 
  

   was 
  greater 
  freedom 
  of 
  motion 
  of 
  the 
  a'ntebrachium 
  upon 
  the 
  brachium, 
  

   and 
  that 
  the 
  flexor 
  and 
  extensor 
  muscles 
  of 
  the 
  forearm 
  were 
  better 
  de- 
  

   veloped 
  than 
  in 
  the 
  existing 
  species. 
  Others 
  are 
  inclined 
  to 
  doubt 
  the 
  

   fact 
  that 
  the 
  elbow-joint 
  of 
  Phocodontia 
  possessed 
  greater 
  mobility 
  than 
  

   that 
  of 
  the 
  existing 
  whales. 
  The 
  molar 
  teeth 
  of 
  the 
  Zeuglodontia 
  or 
  

   Phocodontia 
  also 
  resemble 
  those 
  of 
  certain 
  Pinnipeds 
  more 
  than 
  they 
  do 
  

   the 
  posterior 
  portion 
  of 
  the 
  series 
  in 
  any 
  existing 
  Cetaceans. 
  

  

  The 
  embryological 
  evidence 
  is 
  quite 
  as 
  conclusive 
  as 
  the 
  paleontolo- 
  

   gical 
  in 
  favor 
  of 
  the 
  idea 
  that 
  the 
  extremely 
  specialized 
  existing 
  whales 
  

   and 
  porpoises 
  have 
  descended 
  from 
  at 
  least 
  amphibious, 
  if 
  not 
  terrestrial 
  

   four-footed 
  carnivorous 
  mammals. 
  As 
  in 
  the 
  embryo 
  of 
  the 
  walrus, 
  

   nearly 
  3 
  inches 
  long, 
  Fig. 
  Ill, 
  the 
  young 
  porpoise. 
  Figs. 
  I 
  and 
  II, 
  its 
  

  

  Fig. 
  I. 
  — 
  Fennile 
  tetus 
  of 
  some 
  Delphinoid 
  form, 
  from 
  the 
  side, 
  natural 
  size. 
  (X. 
  M. 
  coll. 
  C8-73. 
  

   cality 
  not 
  known. 
  

   Fig. 
  II. 
  — 
  Tail 
  of 
  the 
  same 
  seen 
  from 
  above. 
  

  

  Lo- 
  

  

  