﻿104 
  CEBUS 
  

  

  variation 
  in 
  the 
  color 
  of 
  pelage 
  among 
  individuals 
  of 
  the 
  three 
  species, 
  

   variegatus, 
  fatuellus, 
  and 
  macrocephalus, 
  and 
  in 
  some 
  cases 
  they 
  

   resemble 
  each 
  other 
  so 
  closely, 
  that 
  unless 
  a 
  definite 
  locality 
  accom- 
  

   panies 
  the 
  example, 
  it 
  is 
  impossible 
  to 
  decide 
  to 
  which 
  species 
  it 
  should 
  

   be 
  referred, 
  and 
  definite 
  localities 
  are 
  rarely 
  given 
  by 
  the 
  Authors 
  of 
  

   the 
  earlier 
  part 
  of 
  the 
  nineteenth 
  century. 
  

  

  Cebus 
  fatuellus 
  peruanus 
  Thomas. 
  

  

  Cebus 
  fatuellus 
  peruanus 
  Thos., 
  Ann. 
  Mag. 
  Nat. 
  Hist., 
  VII, 
  7th 
  

   Ser., 
  1901, 
  p. 
  178. 
  

  

  Type 
  locality. 
  Marcapata, 
  Huoynapata, 
  Inambari 
  Valley, 
  S. 
  E. 
  

   Peru. 
  Type 
  in 
  British 
  Museum. 
  

  

  Genl. 
  Char. 
  Like 
  C. 
  fatuellus, 
  but 
  horns 
  not 
  quite 
  so 
  much 
  

   developed, 
  and 
  the 
  yellow 
  in 
  the 
  arms 
  absent. 
  

  

  Color. 
  Precisely 
  like 
  C. 
  fatuellus 
  as 
  described, 
  but 
  arms 
  from 
  

   shoulders 
  to 
  elbow 
  same 
  color 
  as 
  back. 
  Black 
  tufts 
  on 
  crown 
  not 
  so 
  

   long. 
  Ex 
  type 
  British 
  Museum. 
  

  

  Measurements. 
  Skull 
  : 
  occipito-nasal 
  length, 
  79 
  ; 
  zygomatic 
  width, 
  

   64; 
  intertemporal 
  width, 
  39; 
  palatal 
  length, 
  29; 
  breadth 
  of 
  braincase, 
  

   51; 
  median 
  length 
  of 
  nasals, 
  15; 
  length 
  of 
  upper 
  molar 
  series, 
  21; 
  

   length 
  of 
  mandible, 
  53; 
  length 
  of 
  lower 
  molar 
  series, 
  27. 
  Ex 
  type 
  

   British 
  Museum. 
  

  

  There 
  are 
  two 
  specimens 
  of 
  this 
  form 
  both 
  immature, 
  and 
  indis- 
  

   tinguishable 
  in 
  color 
  from 
  C. 
  fatuellus, 
  except 
  that 
  the 
  upper 
  part 
  of 
  

   the 
  arms 
  is 
  like 
  the 
  back 
  instead 
  of 
  being 
  yellowish. 
  I 
  attribute 
  this 
  

   to 
  age, 
  or 
  possibly 
  season, 
  and 
  the 
  shorter 
  tufts 
  on 
  head 
  to 
  age 
  or 
  

   possibly 
  sex, 
  as 
  both 
  the 
  specimens 
  are 
  females. 
  The 
  examples 
  may 
  

   probably 
  prove 
  to 
  be 
  the 
  young 
  of 
  C. 
  fatuellus. 
  

  

  Cebus 
  macrocephalus 
  Spix. 
  

  

  Cebus 
  macrocephalus 
  Spix, 
  Sim. 
  et 
  Vespert. 
  Bras., 
  1823, 
  p. 
  3, 
  

   pi. 
  I; 
  Wagn., 
  Schreb., 
  Saugth. 
  Suppl., 
  I, 
  1840, 
  p. 
  208; 
  V, 
  

   1855, 
  p. 
  96 
  ; 
  von 
  Pelz., 
  Zool.-Bot. 
  Ges. 
  Wien, 
  1883, 
  Beiheft, 
  

   p. 
  12; 
  Goldi, 
  Os. 
  Mamm, 
  Bras., 
  1893, 
  p. 
  43, 
  (note). 
  

  

  Cebus 
  robustus 
  Tschud., 
  Faun. 
  Peruan., 
  1840, 
  pp. 
  41, 
  45, 
  (nee 
  

   Kuhl, 
  nee 
  Wied). 
  

  

  Cebus 
  (Eucebus) 
  macrocephalus 
  Reichenb., 
  Vollstand. 
  Naturg. 
  

   Affen, 
  1862, 
  p. 
  56, 
  pi. 
  VI, 
  fig. 
  87. 
  

  

  Cebus 
  fatuellus 
  Forbes, 
  Handb. 
  Primates, 
  I, 
  1894, 
  p. 
  211, 
  (Part.). 
  

  

  