﻿326 
  

  

  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  

  

  VOL. 
  98 
  

  

  "Untufted" 
  

  

  (Cebus 
  capucinus, 
  C. 
  albifrons, 
  C. 
  

   nigriviilalus) 
  

  

  (Pis. 
  15, 
  o; 
  16, 
  a) 
  

  

  1. 
  Temporal 
  ridges 
  weakly 
  developed, 
  

   more 
  or 
  less 
  parallel-sided, 
  never 
  con- 
  

   verging 
  to 
  form 
  a 
  sagittal 
  crest. 
  

  

  2. 
  Bony 
  rings 
  encircling 
  orbits 
  joined 
  

   at 
  roots 
  of 
  nasals 
  to 
  form 
  well-defined, 
  

   nearly 
  horizontal 
  superciliary 
  ridges. 
  

   Frontals 
  above 
  orbits 
  plane 
  or 
  slightly 
  

   rounded 
  in 
  males, 
  more 
  rounded 
  in 
  

   females. 
  

  

  3. 
  Brain 
  case 
  relatively 
  low, 
  dolicho- 
  

   cephahc. 
  

  

  4. 
  Ramus 
  of 
  mandible 
  in 
  males 
  

   comparatively 
  low, 
  depth 
  from 
  condyle 
  

   usually 
  less 
  than 
  length 
  of 
  C-M^; 
  in 
  

   females, 
  mandible 
  weaker 
  A\ith 
  ramus 
  

   relatively 
  lower. 
  

  

  5. 
  Vomer 
  situated 
  more 
  posteriorly, 
  

   the 
  vertical 
  plate 
  nearly 
  always 
  well 
  ex- 
  

   posed 
  behind 
  plane 
  of 
  posterior 
  border 
  

   of 
  palate; 
  wings 
  of 
  vomer 
  heavy, 
  little, 
  

   or 
  not 
  at 
  all 
  separated 
  from 
  each 
  other, 
  

   the 
  presphenoid, 
  if 
  present, 
  not 
  visible 
  

   from 
  ventral 
  aspect. 
  

  

  6. 
  Pterygoid 
  fossa 
  and 
  posterior 
  

   narial 
  openings 
  wider, 
  the 
  internal 
  

   pterygoid 
  plate 
  and 
  hamular 
  processes 
  

   tending 
  to 
  converge. 
  

  

  None 
  of 
  the 
  above 
  characters 
  are 
  absolute. 
  It 
  is 
  believed, 
  however, 
  

   that 
  any 
  normal 
  adult 
  skull 
  selected 
  at 
  random 
  can 
  be 
  correctly 
  

   classified 
  by 
  a 
  judicious 
  determination 
  of 
  which 
  set 
  of 
  cranial 
  charac- 
  

   ters 
  best 
  applies. 
  This, 
  taken 
  together 
  with 
  external 
  characters 
  given 
  

   below, 
  should 
  be 
  ample 
  for 
  positive 
  identification. 
  

  

  "Tufted" 
  

   {Cebus 
  apella) 
  

  

  (Pis. 
  15, 
  5; 
  16, 
  6) 
  

  

  1. 
  Temporal 
  ridges 
  more 
  developed, 
  

   convergent, 
  in 
  old 
  males 
  uniting 
  to 
  

   form 
  a 
  sagittal 
  crest. 
  

  

  2. 
  Superciliary 
  ridges 
  weak 
  or 
  obso- 
  

   lete; 
  temporal 
  ridges 
  rising 
  obhquely 
  up 
  

   and 
  back 
  from 
  bony 
  rings 
  of 
  orbits 
  to 
  

   define 
  a 
  triangular-shaped 
  forehead 
  in 
  

   adult 
  males 
  and 
  old 
  females. 
  Frontal 
  

   region 
  above 
  orbits 
  always 
  forming 
  a 
  

   convex 
  eminence 
  with 
  a 
  pronounced 
  

   vaulting 
  in 
  females. 
  

  

  3. 
  Brain 
  case 
  more 
  vaulted, 
  let>s 
  

   dolichocephalic. 
  

  

  4. 
  Ramus 
  of 
  mandible 
  in 
  males 
  com- 
  

   paratively 
  high, 
  depth 
  from 
  condyle 
  

   usually 
  more 
  than 
  length 
  of 
  C-M^; 
  in 
  

   females, 
  mandible 
  generally 
  as 
  in 
  

   males 
  of 
  "untufted" 
  but 
  with 
  ramus 
  

   averaging 
  relatively 
  higher. 
  

  

  5. 
  Vomer 
  situated 
  more 
  anteriorly, 
  

   the 
  vertical 
  plate 
  hardly, 
  or 
  not 
  at 
  all, 
  

   exposed 
  behind 
  plane 
  of 
  posterior 
  

   border 
  of 
  palate; 
  wings 
  of 
  vomer 
  more 
  

   delicate, 
  well 
  spread, 
  revealing 
  a 
  pre- 
  

   sphenoid 
  (normally 
  distinct 
  but 
  may 
  be 
  

   fused 
  to 
  basisphenoid, 
  especially 
  in 
  old 
  

   males). 
  

  

  6. 
  Pterygoid 
  fossa 
  and 
  narial 
  open- 
  

   ings 
  narrower, 
  the 
  internal 
  pterygoid 
  

   plates 
  more 
  nearly 
  parallei-sided, 
  the 
  

   hamular 
  processes 
  tending 
  to 
  diverge. 
  

  

  "Untufted" 
  

  

  {Cebus 
  capucinus, 
  C. 
  albifrons, 
  C. 
  

   nigrivittatus) 
  

  

  1. 
  Frontal 
  tufts 
  normally 
  absent 
  in 
  

   males; 
  when 
  present 
  in 
  females, 
  placed 
  

   weU 
  forward 
  and 
  in 
  form 
  of 
  superciliary 
  

   brush 
  or 
  frontal 
  diadem 
  with 
  the 
  long, 
  

   erect 
  hairs 
  radiating 
  from 
  midfrontal 
  

  

  "Tufted" 
  

   {Cebus 
  apella) 
  

  

  1. 
  Frontal 
  tufts 
  usually 
  present 
  in 
  

   adults 
  of 
  both 
  sexes; 
  tufts 
  may 
  be 
  

   paired 
  with 
  one 
  on 
  each 
  side 
  of 
  crown 
  in 
  

   form 
  of 
  "horns," 
  ridges, 
  or 
  lines 
  of 
  

   short 
  erect 
  hairs, 
  or 
  as 
  a 
  single 
  brushlike 
  

  

  