﻿24 
  PROCEEDINGS 
  OF 
  THE 
  NATIONAL 
  MUSEUM 
  vol. 
  96 
  

  

  Distribution. 
  — 
  South 
  side 
  of 
  Eio 
  Amazonas, 
  between 
  the 
  Rio 
  Tapa- 
  

   joz 
  and 
  Rio 
  Tocantins, 
  state 
  of 
  Para, 
  Brazil. 
  

  

  General 
  characters. 
  — 
  A 
  deep, 
  glossy-black 
  spider 
  monkey, 
  with 
  a 
  

   white 
  semilunar 
  forehead 
  patch 
  and 
  a 
  few 
  white 
  side 
  whiskers 
  on 
  

   face. 
  Similar 
  in 
  general 
  to 
  helzehuth., 
  which 
  it 
  resembles 
  in 
  the 
  pos- 
  

   session 
  of 
  a 
  conspicuous 
  forehead 
  patch, 
  but 
  the 
  pelage 
  is 
  longer 
  (long- 
  

   est 
  hairs 
  on 
  back 
  about 
  90 
  instead 
  of 
  50 
  mm.) 
  and 
  it 
  differs 
  notably 
  in 
  

   the 
  extension 
  of 
  black 
  over 
  entire 
  body 
  and 
  limbs. 
  Differs 
  from 
  panis- 
  

   cus 
  of 
  the 
  opposite 
  side 
  of 
  the 
  Rio 
  Amazonas 
  in 
  smaller 
  size, 
  especially 
  

   the 
  smaller 
  foot, 
  shorter 
  pelage, 
  and 
  in 
  the 
  conspicuous 
  white 
  forehead 
  

   patch 
  (absent 
  in 
  paniscus) 
  ; 
  cranial 
  details 
  also 
  different. 
  

  

  Color. 
  — 
  An 
  adult 
  male 
  from 
  Caxiricatuba, 
  east 
  bank 
  of 
  Rio 
  Tapajoz, 
  

   Para, 
  Brazil 
  : 
  Face 
  flesh-colored, 
  at 
  least 
  around 
  eyes 
  and 
  on 
  nose 
  ; 
  

   side 
  whiskers 
  white 
  mixed 
  with 
  black; 
  a 
  narrow 
  strip 
  across 
  brow 
  just 
  

   above 
  eyes 
  thinly 
  clothed 
  with 
  erect 
  black 
  hairs 
  behind 
  which 
  is 
  a 
  

   white 
  semilunar 
  forehead 
  patch 
  overlapped 
  behind 
  by 
  black 
  hairs 
  from 
  

   crown 
  ; 
  rest 
  of 
  upper 
  and 
  underparts 
  deep, 
  glossy 
  black. 
  

  

  Skull. 
  — 
  Very 
  similar 
  to 
  that 
  of 
  hehehuth 
  but 
  interorbital 
  region 
  

   more 
  depressed. 
  Compared 
  with 
  that 
  of 
  paniscus 
  the 
  interorbital 
  

   region 
  is 
  more 
  depressed 
  and 
  the 
  anterior 
  profile 
  rises 
  more 
  steeply 
  to 
  

   vault 
  of 
  brain 
  case; 
  it 
  also 
  differs 
  notably 
  in 
  the 
  lesser 
  posterior 
  exten- 
  

   sion 
  of 
  the 
  external 
  reduplications 
  of 
  the 
  pterygoids 
  and 
  the 
  smaller 
  

   winglike 
  tips. 
  

  

  Measurements. 
  — 
  An 
  adult 
  male 
  from 
  Caxiricatuba, 
  east 
  bank 
  of 
  

   Rio 
  Tapajoz, 
  Para, 
  Brazil: 
  Total 
  length, 
  1,250 
  mm.; 
  tail, 
  750; 
  hind 
  

   foot, 
  108 
  (188 
  ?). 
  Three 
  females 
  from 
  Marai, 
  right 
  bank 
  of 
  Rio 
  

   Tapajoz 
  as 
  stated 
  by 
  Lonnberg 
  (Arkiv 
  for 
  ZooL, 
  vol. 
  32A, 
  No. 
  25, 
  p. 
  7, 
  

   July 
  18, 
  1940), 
  respectively 
  : 
  Total 
  length, 
  1,114, 
  1,190, 
  1,245; 
  tail, 
  770, 
  

   613, 
  740; 
  hind 
  foot, 
  190, 
  189, 
  190. 
  Skull: 
  Adult 
  male 
  from 
  Caxirica- 
  

   tuba, 
  Rio 
  Tapajoz, 
  Para, 
  Brazil 
  : 
  Greatest 
  length, 
  114.1 
  ; 
  orbital 
  width, 
  

   61.3; 
  postorbital 
  constriction, 
  49.5; 
  width 
  of 
  brain 
  case, 
  59.6; 
  zygo- 
  

   matic 
  breadth, 
  69.7; 
  maxillary 
  tooth 
  row, 
  31.9, 
  

  

  Remarks. 
  — 
  A. 
  h. 
  marginatu^s 
  is 
  readily 
  distinguished 
  by 
  the 
  white 
  

   semilunar 
  forehead 
  patch 
  combined 
  with 
  black 
  general 
  coloration. 
  It 
  

   appears 
  to 
  be 
  most 
  closely 
  allied 
  to 
  helzehuth 
  but 
  differs 
  in 
  color 
  pat- 
  

   tern 
  and 
  in 
  longer 
  pelage. 
  In 
  length 
  of 
  pelage 
  it 
  suggests 
  paniscus, 
  

   which 
  inhabits 
  the 
  opposite 
  bank 
  of 
  the 
  Rio 
  Amazonas, 
  but 
  is 
  less 
  

   extreme, 
  as 
  the 
  longer 
  hairs 
  on 
  the 
  middle 
  of 
  the 
  back 
  in 
  that 
  form 
  

   exceed 
  100 
  mm. 
  in 
  length. 
  In 
  cranial 
  characters 
  also 
  it 
  agrees 
  more 
  

   closely 
  with 
  helzehuth 
  than 
  paniscus. 
  

  

  This 
  black 
  spider 
  monkey 
  with 
  white 
  semilunar 
  patch 
  on 
  forehead 
  

   and 
  white 
  side 
  whiskers 
  seems 
  to 
  be 
  most 
  abundant 
  between 
  the 
  Rio 
  

   Tapajoz 
  and 
  the 
  Rio 
  Xingii. 
  Specimens 
  in 
  the 
  Museu 
  Goeldi 
  at 
  

   Belem 
  were 
  obtained 
  at 
  Altamira 
  on 
  the 
  Rio 
  Xingu 
  and 
  at 
  Santarem 
  at 
  

   the 
  mouth 
  of 
  the 
  Rio 
  Tapajoz. 
  Lonnberg 
  (Arkiv 
  for 
  ZooL, 
  vol. 
  32A, 
  

  

  