﻿446 
  REPORT 
  OF 
  COMMISSIONER 
  OF 
  FISH 
  AND 
  FISHERIES. 
  [20] 
  

  

  the 
  first 
  phalanx 
  of 
  the 
  hallux; 
  some 
  of 
  its 
  fibers 
  extending 
  to 
  the 
  distal 
  

   end 
  of 
  that 
  phalanx. 
  In 
  one 
  foot 
  of 
  this 
  seal 
  the 
  hinder 
  margin 
  of 
  the 
  

   gracilis 
  tendon 
  was 
  also 
  thick, 
  and 
  formed 
  or 
  contributed 
  to 
  form 
  the 
  

   superficial 
  flexor 
  tendon 
  of 
  the 
  fifth 
  digit. 
  

  

  In 
  Phoca 
  the 
  muscles 
  of 
  the 
  front 
  of 
  the 
  abdomen 
  overhung 
  the 
  knee; 
  

   aud 
  when 
  these 
  were 
  removed 
  a 
  wide, 
  deep 
  chasm 
  was 
  exposed 
  between 
  

   the 
  loug 
  pubes, 
  on 
  the 
  one 
  side, 
  and 
  the 
  thigh, 
  knee, 
  aud 
  leg 
  on 
  the 
  

   other. 
  This 
  chasm 
  was 
  crossed 
  by 
  a 
  large 
  muscle 
  passing 
  from 
  the 
  side 
  

   of 
  the 
  symphysis 
  pubis 
  to 
  the 
  front 
  of 
  the 
  upper 
  part 
  of 
  the 
  leg 
  and 
  knee 
  

   beneath 
  the 
  gracilis. 
  It 
  may 
  perhaps 
  be 
  regarded 
  as 
  an 
  adductor 
  mag- 
  

   mis. 
  

  

  Gluteus 
  maximus 
  in 
  Phoca 
  arose 
  from 
  the 
  back 
  of 
  the 
  crest 
  of 
  the 
  

   ilium, 
  the 
  sacral 
  spines, 
  and 
  the 
  sacro-iliac 
  ligaments, 
  and 
  was 
  attached 
  

   to 
  the 
  trochanter 
  and 
  the 
  external 
  supra-condyloid 
  ridge 
  of 
  the 
  femur, 
  

   while 
  its 
  lower 
  part 
  expanded 
  over 
  the 
  knee 
  joint. 
  Some 
  of 
  its 
  fibers 
  

   were 
  continuous 
  with 
  those 
  of 
  the 
  vastus 
  externus. 
  

  

  This 
  somewhat 
  extended 
  discussion 
  of 
  the 
  muscular 
  anatomy 
  of 
  the 
  

   hind 
  limbs 
  of 
  the 
  Pinnipedia 
  has 
  been 
  thought 
  necessary 
  in 
  order 
  to 
  

   bring 
  out 
  as 
  prominently 
  as 
  possible 
  the 
  fact 
  that 
  some 
  of 
  the 
  insertions 
  

   of 
  the 
  muscles 
  of 
  the 
  hiud 
  limb 
  have 
  really 
  traveled 
  backward 
  behind 
  

   their 
  usual 
  position 
  on 
  the 
  bones 
  of 
  the 
  same 
  pair 
  of 
  limbs 
  of 
  normal 
  

   Mammalia. 
  This 
  is 
  obviously 
  a 
  teleological 
  modification, 
  or 
  one 
  which 
  

   lias 
  been 
  needed 
  in 
  order 
  to 
  make 
  the 
  muscles 
  more 
  effective 
  upon 
  the 
  

   distal 
  or 
  exserted 
  part 
  of 
  the 
  limb 
  or 
  the 
  pes. 
  The 
  fact 
  that 
  the 
  ab- 
  

   dominal 
  muscles 
  overlap 
  or 
  extend 
  over 
  the 
  knees 
  of 
  Phoca 
  shows 
  how 
  

   real 
  is 
  this 
  backward 
  extension 
  of 
  the 
  musculature 
  of 
  the 
  body, 
  which 
  

   has 
  been 
  obviously 
  aided 
  by 
  the 
  shortening 
  of 
  the 
  femur 
  and 
  lengthen- 
  

   ing 
  of 
  the 
  cms 
  in 
  this 
  type, 
  the 
  Pinnipedia. 
  In 
  one 
  case 
  even 
  the 
  origin 
  

   of 
  a 
  muscular 
  pair 
  seems 
  to 
  have 
  been 
  pushed 
  backward 
  somewhat 
  ; 
  it 
  

   is 
  that 
  of 
  the 
  muscle 
  called 
  the 
  caudo-tibialis 
  by 
  Huxley, 
  and 
  regarded 
  

   by 
  him 
  as 
  the 
  homologue 
  of 
  the 
  semimembranosus 
  and 
  semitendinosus 
  of 
  

   normal 
  mammals. 
  

  

  Quoting 
  again 
  from 
  Humphrey, 
  I 
  may 
  illustrate 
  the 
  fact 
  that 
  the 
  

   posterior 
  girdle 
  and 
  muscles 
  of 
  the 
  pinniped 
  are 
  actually 
  undergcing 
  

   degeneration 
  in 
  certain 
  directions. 
  He 
  says 
  : 
  a 
  In 
  the 
  seal 
  the 
  terminal 
  

   parts 
  of 
  the 
  limbs, 
  especially 
  of 
  the 
  hind 
  limbs, 
  are 
  large, 
  and 
  spread 
  

   out 
  fan-like, 
  the 
  digits 
  being 
  thin, 
  long, 
  of 
  nearly 
  equal 
  length, 
  and 
  in 
  

   the 
  same 
  plane 
  ; 
  and 
  the 
  size 
  of 
  the 
  fau 
  is 
  increased 
  or 
  diminished 
  in 
  

   each 
  foot, 
  chiefly 
  by 
  the 
  distancing 
  or 
  approximating 
  of 
  the 
  other 
  digits 
  

   to 
  the 
  first, 
  and 
  the 
  lateral 
  movement 
  of 
  the 
  digits 
  therefore 
  increases 
  

   from 
  the 
  first 
  to 
  the 
  fifth. 
  The 
  dorsal 
  and 
  plantar 
  surfaces 
  of 
  the 
  ter- 
  

   minal 
  parts 
  of 
  the 
  hind 
  limb 
  are 
  in 
  the 
  same 
  plane 
  with 
  those 
  of 
  the 
  

   leg 
  ; 
  the 
  projecting 
  part 
  of 
  the 
  heel-bone, 
  which 
  is 
  small, 
  is 
  drawn 
  for- 
  

   ward 
  or 
  upward, 
  and 
  the 
  hinder 
  part 
  of 
  the 
  astragulus, 
  carrying 
  the 
  

   groove 
  for 
  the 
  flexor 
  tendon 
  of 
  the 
  toes, 
  is 
  draw 
  up 
  with 
  and 
  projects 
  

   nearly 
  as 
  far. 
  The 
  lumbar 
  and 
  hinder 
  five 
  or 
  six 
  dorsal 
  vertebra} 
  are 
  

  

  