﻿22 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  96 
  

  

  ground 
  color 
  thinlj^ 
  overlaid 
  with 
  long 
  black 
  hairs 
  (not 
  numerous 
  

   enough 
  to 
  materially 
  affect 
  the 
  general 
  ground 
  color) 
  ; 
  hairs 
  on 
  throat 
  

   normally 
  black, 
  sometimes 
  .grayish, 
  more 
  or 
  less 
  concealed 
  by 
  black 
  

   hairs 
  ; 
  tail 
  normally 
  bicolored, 
  the 
  upper 
  surface 
  black 
  and 
  the 
  under 
  

   surface 
  similar 
  to 
  that 
  of 
  underparts 
  (in 
  occasional 
  specimens 
  the 
  

   upper 
  surface 
  is 
  about 
  the 
  same 
  as 
  that 
  of 
  the 
  under 
  surface, 
  but 
  more 
  

   heavily 
  interspersed 
  with 
  long 
  black 
  overhairs). 
  

  

  Skull. 
  — 
  About 
  as 
  in 
  that 
  of 
  hyhridus. 
  Very 
  similar 
  in 
  general 
  to 
  

   that 
  of 
  fanhcus 
  but 
  brain 
  case 
  somewhat 
  narrower 
  ; 
  posterior 
  borders 
  

   of 
  external 
  reduplications 
  of 
  pterygoids 
  more 
  deeply 
  concave. 
  

  

  Measurements. 
  — 
  ^An 
  adult 
  male 
  and 
  female 
  from 
  El 
  Llagual, 
  Caura 
  

   District, 
  Venezuela, 
  respectively 
  : 
  Total 
  length, 
  1,257, 
  1,317 
  mm. 
  ; 
  tail, 
  

   823, 
  810; 
  hind 
  foot, 
  — 
  , 
  193. 
  An 
  adult 
  male 
  and 
  female 
  from 
  Valle 
  de 
  

   los 
  Monos, 
  Mount 
  Duida, 
  Venezuela, 
  respectively: 
  Total 
  length, 
  1,110, 
  

   1,330; 
  tail, 
  695, 
  840; 
  hind 
  foot, 
  185, 
  195. 
  Skull: 
  An 
  adult 
  male 
  and 
  

   female 
  from 
  El 
  Llagual, 
  Venezuela, 
  respectively: 
  Greatest 
  length, 
  

   109.5, 
  117.7; 
  orbital 
  width, 
  60.2, 
  61.8; 
  postorbital 
  constriction, 
  50, 
  51; 
  

   width 
  of 
  brain 
  case, 
  59.7, 
  59.8; 
  zygomatic 
  width, 
  68.3, 
  66.7; 
  maxillary 
  

   tooth 
  row, 
  29.8, 
  28.8. 
  An 
  adult 
  male 
  and 
  female 
  from 
  Valle 
  de 
  los 
  

   Monos, 
  Venezuela, 
  respectively 
  : 
  Greatest 
  length, 
  119.4, 
  113.2 
  ; 
  orbital 
  

   width, 
  61.6, 
  61; 
  postorbital 
  constriction, 
  52, 
  52.1; 
  width 
  of 
  brain 
  case, 
  

   61, 
  63.2 
  ; 
  zygomatic 
  width, 
  71.9, 
  68.4 
  ; 
  maxillary 
  tooth 
  row, 
  29.9, 
  30. 
  

  

  Remarks. 
  — 
  This 
  well-marked 
  and 
  widely 
  dispersed 
  spider 
  monkey 
  

   has 
  evidently 
  been 
  described 
  under 
  various 
  names 
  which 
  appear 
  to 
  be 
  

   assignable 
  to 
  the 
  synonymy 
  of 
  hehehuth. 
  Humboldt 
  (Recueil 
  d'obser- 
  

   vations 
  de 
  zoologie 
  et 
  d'anatomie 
  comparee, 
  vol. 
  1, 
  livr. 
  7, 
  p. 
  353, 
  1812) 
  

   observed 
  that 
  it 
  was 
  found 
  along 
  the 
  banks 
  of 
  the 
  Rio 
  Orinoco 
  but 
  

   always 
  above 
  the 
  Eaudal 
  de 
  Atures 
  and 
  the 
  Raudal 
  de 
  Maipures 
  in 
  

   Venezuela. 
  Allen 
  records 
  specimens 
  from 
  La 
  Union 
  on 
  the 
  Rio 
  Caura 
  

   (Bull. 
  Amer. 
  Mus. 
  Nat. 
  Hist., 
  vol. 
  20, 
  No. 
  29, 
  p. 
  344, 
  Oct. 
  8, 
  1904) 
  as 
  

   well 
  as 
  from 
  the 
  Rio 
  Mato, 
  a 
  tributary 
  of 
  the 
  Rio 
  Caura 
  (Bull. 
  Amer. 
  

   Mus. 
  Nat. 
  Hist., 
  vol. 
  28, 
  No. 
  12, 
  p. 
  148, 
  May 
  27, 
  1910) 
  and 
  from 
  El 
  

   Llagual 
  on 
  the 
  Rio 
  Caura, 
  Venezuela 
  (Bull. 
  Amer. 
  Mus. 
  Nat. 
  Hist., 
  

   vol. 
  30, 
  No. 
  10, 
  p. 
  272, 
  Dec. 
  2, 
  1911). 
  Johann 
  Natterer 
  in 
  February 
  

   1831 
  obtained 
  a 
  male, 
  three 
  females, 
  and 
  a 
  young 
  of 
  this 
  spider 
  monkey 
  

   at 
  Serra 
  de 
  Cocoi 
  on 
  the 
  upper 
  Rio 
  Negro, 
  Brazil, 
  one 
  female 
  of 
  which 
  

   was 
  exchanged 
  with 
  the 
  British 
  Museum 
  of 
  Natural 
  History 
  (Sclater, 
  

   Proc. 
  Zool. 
  Soc. 
  London 
  for 
  1871, 
  pp. 
  39, 
  225, 
  1871). 
  

  

  According 
  to 
  Bartlett 
  (Proc. 
  Zool. 
  Soc. 
  London 
  for 
  1871, 
  p. 
  217), 
  

   this 
  spider 
  monkey 
  is 
  found 
  in 
  Peru 
  in 
  the 
  interior 
  forest 
  on 
  the 
  moun- 
  

   tain 
  range 
  between 
  Lamas 
  (north 
  of 
  Rio 
  Mayo, 
  a 
  tributary 
  of 
  Rio 
  Hual- 
  

   laga) 
  and 
  Saravacu 
  on 
  Rio 
  Ucayali; 
  on 
  the 
  lower 
  spurs 
  of 
  the 
  moun- 
  

   tains 
  between 
  Moyobamba 
  and 
  the 
  Rio 
  Huallaga 
  ; 
  at 
  Cahuapanas 
  on 
  

   the 
  headwaters 
  of 
  the 
  Rio 
  Cahaupanas, 
  a 
  tributary 
  of 
  the 
  Rio 
  Ma- 
  

   raiion; 
  near 
  the 
  native 
  village 
  of 
  Chamicuros 
  (Parinari 
  District) 
  on 
  

  

  