﻿MAMMALS 
  OF 
  NORTHERN 
  COLOMBIA 
  — 
  HERSHKOVITZ 
  393 
  

  

  and 
  Tarra 
  howlers 
  to 
  be 
  darker 
  than 
  the 
  others. 
  This 
  may 
  indicate 
  

   intergradation 
  with 
  the 
  distinctly 
  darker 
  arctoidea 
  Cabrera 
  (for 
  

   ursina 
  Humboldt, 
  preoccupied). 
  One 
  available 
  specimen 
  of 
  the 
  latter 
  

   from 
  the 
  Paria 
  Peninsula, 
  northern 
  Venezuela, 
  is 
  almost 
  blackish 
  in 
  

   contrast 
  with 
  typical 
  representatives 
  of 
  seniculus. 
  

  

  The 
  female 
  skull 
  of 
  the 
  present 
  series 
  is 
  imperfect. 
  An 
  injury 
  to 
  

   the 
  left 
  side 
  resulted 
  in 
  a 
  fracture 
  of 
  the 
  maxillary 
  and 
  lachrymal 
  por- 
  

   tions 
  of 
  the 
  zygomatic 
  arch 
  as 
  well 
  as 
  damage 
  to 
  the 
  orbit 
  itself. 
  The 
  

   monkey 
  had 
  evidently 
  recovered 
  from 
  the 
  effects 
  of 
  the 
  injury 
  though 
  

   the 
  wound 
  itself 
  appears 
  to 
  be 
  no 
  more 
  than 
  half 
  healed. 
  

  

  It 
  is 
  rather 
  curious 
  that 
  the 
  only 
  howlers 
  of 
  the 
  collection 
  with 
  

   important 
  cranial 
  injuries 
  are 
  two 
  females 
  with 
  damaged 
  left 
  zygo- 
  

   matic 
  arches. 
  To 
  this 
  may 
  be 
  added 
  another 
  female 
  of 
  the 
  A. 
  

   palliata 
  group 
  used 
  in 
  this 
  report 
  for 
  comparisons, 
  also 
  with 
  a 
  dam- 
  

   aged 
  left 
  arch. 
  

  

  HYOID 
  BONE 
  OF 
  HOWLERS, 
  GENUS 
  ALOUATTA 
  

  

  Hyoid 
  bones 
  of 
  Alouatta 
  seniculus 
  (32 
  males, 
  28 
  females) 
  collected 
  

   by 
  the 
  author 
  in 
  northern 
  Colombia 
  form 
  the 
  principal 
  basis 
  for 
  the 
  

   following 
  descriptions. 
  Other 
  hyoids 
  of 
  A. 
  seniculus 
  from 
  tlu'oughout 
  

   the 
  range 
  of 
  the 
  species 
  have 
  been 
  examined. 
  Further 
  comparisons 
  

   have 
  been 
  made 
  with 
  hyoids 
  of 
  three 
  males 
  and 
  one 
  female 
  of 
  A. 
  

   palliata, 
  of 
  one 
  male 
  of 
  helzehul, 
  of 
  two 
  females 
  of 
  nigerrima, 
  of 
  a 
  

   male 
  and 
  female 
  oi 
  fusca, 
  and 
  of 
  a 
  male 
  of 
  carayaJ 
  

  

  The 
  value 
  of 
  the 
  hyoidan 
  structure 
  for 
  classifying 
  species 
  of 
  

   Alouatta 
  was 
  first 
  demonstrated 
  by 
  Ihering 
  (1914). 
  His 
  material 
  

   consisted 
  of 
  several 
  hyoids 
  representing 
  seniculus, 
  helzehul, 
  Jusca, 
  and 
  

   caraya. 
  Lonnberg 
  (1941, 
  pp. 
  2-5) 
  also 
  made 
  a 
  study 
  of 
  howler 
  

   hyoids. 
  He 
  described 
  and 
  figured 
  those 
  of 
  a 
  few 
  males 
  of 
  A. 
  seniculus, 
  

   one 
  each 
  from 
  the 
  following 
  localities: 
  Rio 
  Jurud, 
  Brazil; 
  Surinam; 
  

   Rio 
  Jahu, 
  east 
  of 
  Rio 
  Negro, 
  Brazil; 
  Guamal, 
  on 
  northern 
  frontier 
  

   between 
  Colombia 
  and 
  Venezuela; 
  and 
  Cartagena, 
  Colombia. 
  Speci- 
  

   mens 
  from 
  the 
  first 
  two 
  localities 
  were 
  identified, 
  respectively, 
  as 
  A. 
  

   seniculus 
  juruana 
  and 
  A. 
  seniculus 
  seniculus. 
  Those 
  of 
  the 
  last 
  

   three 
  localities 
  were 
  regarded 
  as 
  different 
  with 
  each 
  representing 
  a 
  

   possibly 
  distinct 
  species. 
  This 
  conclusion 
  does 
  not 
  appear 
  to 
  be 
  

   tenable. 
  Lonnberg's 
  published 
  figures 
  of 
  the 
  different 
  kinds 
  of 
  hyoid 
  

   bones 
  of 
  red 
  howlers 
  of 
  the 
  seniculus 
  group 
  hardly 
  show 
  the 
  full 
  range 
  

   of 
  variation 
  that 
  exists 
  in 
  any 
  large 
  series 
  of 
  A. 
  seniculus. 
  The 
  same 
  

   author 
  also 
  described 
  and 
  figured 
  (op. 
  cit., 
  pp. 
  24-25, 
  pi. 
  3, 
  figs. 
  

   6a-b) 
  the 
  male 
  hyoid 
  bone 
  of 
  A. 
  heniensis, 
  a 
  red 
  howler 
  of 
  the 
  A. 
  

   jusca 
  group. 
  Cruz 
  Lima 
  (1945, 
  pp. 
  68-69) 
  included 
  some 
  characters 
  

   of 
  the 
  hyoid 
  in 
  his 
  key 
  to 
  the 
  Amazonian 
  howlers, 
  A. 
  seniculus, 
  

   helzehul, 
  and 
  nigerrima. 
  

  

  ' 
  Except 
  for 
  the 
  hyoid 
  of 
  one 
  A. 
  palliata, 
  ull 
  specimens 
  of 
  the 
  last-mentioned 
  species 
  are 
  in 
  the 
  collection 
  

   of 
  the 
  Chicago 
  Natiural 
  History 
  Museum. 
  

  

  