﻿504 
  rnocEEDTxas 
  of 
  tee 
  national 
  museum. 
  

  

  States. 
  The 
  skull 
  is 
  large, 
  measuring 
  47.5 
  by 
  23 
  mm. 
  in 
  extreme 
  dimen- 
  

   sions. 
  The 
  genoral 
  slin]ie 
  is 
  suggestive 
  of 
  that 
  of 
  K. 
  leurodo)i. 
  It 
  lias 
  

   the 
  same 
  piomiiieiit 
  piemaxilla', 
  ending 
  posteriorly 
  well 
  behind 
  the 
  

   nasals. 
  The 
  skull 
  is 
  lower 
  and 
  more 
  convex 
  antero-posteriorly 
  than 
  

   that 
  of 
  N. 
  Icucodon, 
  with 
  the 
  brain-case 
  much 
  more 
  tlat. 
  It 
  is 
  more 
  

   angular 
  throughout, 
  with 
  zj'gomatic 
  arches 
  standing 
  out 
  more 
  squarely 
  

   anteriorly. 
  The 
  interparietal 
  bone 
  is 
  less 
  quadrate, 
  being 
  wider, 
  and 
  

   more 
  jjointed 
  posteriorly 
  ; 
  and 
  the 
  nasal 
  bones 
  differ 
  markedly 
  in 
  having 
  

   a 
  prominent 
  swelling 
  anteriorly, 
  which 
  gives 
  the 
  pair 
  a 
  distinctly 
  spat- 
  

   ulate 
  form, 
  as 
  in 
  Sigmodon 
  hisindus 
  eremicus 
  from 
  the 
  same 
  region. 
  

  

  SIGMODON 
  HISPIDUS 
  PALLIDUS, 
  new 
  subspecies. 
  

   EASTERN 
  DESEET 
  COTTON 
  RAT. 
  

  

  Ty2)e.—^o. 
  f 
  Htf? 
  U.S.N.M. 
  (Collection 
  International 
  Boundary 
  Com- 
  

   mission). 
  Adult 
  male, 
  from 
  the 
  left 
  bank 
  of 
  the 
  IJio 
  Grande, 
  about 
  (> 
  

   miles 
  above 
  El 
  I'aso, 
  Texas, 
  and 
  op])osite 
  the 
  initial 
  monument 
  of 
  the 
  

   Mexican 
  boundary. 
  Collected 
  by 
  Doctor 
  Edgar 
  A. 
  Mearns 
  and 
  Mr. 
  F. 
  

   X. 
  Holzner, 
  February 
  19, 
  18(12, 
  Original 
  number, 
  1401. 
  

  

  DescHption 
  of 
  type. 
  — 
  Smaller 
  than 
  Sigmodon 
  hispid 
  us 
  texvoius, 
  v^\t\i 
  

   the 
  ears 
  relatively 
  and 
  actually 
  larger. 
  Color 
  much 
  paler 
  and 
  grayer, 
  

   the 
  brown 
  color 
  being 
  replaced 
  by 
  gray. 
  Above 
  buffy 
  gray, 
  finely 
  

   mixed 
  Avith 
  black, 
  producing 
  a 
  finely-blended 
  grizzle. 
  Feet 
  grayish 
  

   white. 
  Under 
  surfaces 
  pure 
  white. 
  Tail 
  dusky 
  brownish 
  above, 
  grayish 
  

   white 
  on 
  sides 
  and 
  below. 
  Length, 
  242 
  mm.; 
  tail 
  to 
  end 
  of 
  vertebnp, 
  

   10.3 
  (to 
  end 
  hairs, 
  108); 
  height 
  of 
  ear 
  from 
  crown, 
  14 
  (from 
  notch, 
  19.5); 
  

   length 
  of 
  head, 
  37; 
  length 
  of 
  hind 
  foot, 
  30. 
  

  

  Geographical 
  range. 
  — 
  This 
  subspecies 
  is 
  known 
  only 
  from 
  the 
  chain 
  

   of 
  old 
  lake 
  basins 
  along 
  the 
  course 
  of 
  the 
  Upper 
  Eio 
  Grande, 
  in 
  the 
  

   Eastern 
  Desert 
  Tract. 
  

  

  SIGMODON 
  HISPIDUS 
  EREMICUS, 
  new 
  subspecies. 
  

   WESTERN 
  DESERT 
  COTTON 
  RAT. 
  

  

  Type.—^o. 
  60319, 
  U.S.N.M. 
  (Collection 
  International 
  Boundary 
  Com- 
  

   mission). 
  Skin 
  and 
  skull. 
  Adult 
  male, 
  from 
  Cienega 
  Well, 
  30 
  miles 
  

   south 
  of 
  monument 
  No. 
  204, 
  Mexican 
  boundary 
  line, 
  on 
  the 
  left 
  bank 
  

   of 
  the 
  Colorado 
  Eiver, 
  in 
  Sonora. 
  Collected 
  by 
  Doctor 
  Edgar 
  A. 
  

   ]\Iearns 
  and 
  Mr. 
  F. 
  X. 
  Holzner, 
  March 
  24, 
  1894. 
  Original 
  number, 
  3307. 
  

  

  Description 
  of 
  type. 
  — 
  General 
  aspect 
  yellowish 
  gray. 
  The 
  usual 
  

   black 
  bands 
  of 
  the 
  hair 
  composing 
  the 
  outer 
  coating 
  are 
  ])ale 
  brown 
  in 
  

   this 
  desert 
  race, 
  and 
  the 
  almost 
  colorless 
  tips 
  of 
  the 
  longest 
  hairs 
  pro- 
  

   duce 
  a 
  peculair 
  haziness. 
  Along 
  the 
  sides, 
  but 
  especially 
  on 
  the 
  rump, 
  

   there 
  is 
  a 
  strong 
  ochraceous 
  tinge. 
  Under 
  surface 
  white, 
  but 
  with 
  

   pale 
  gray 
  underfur 
  showing 
  between 
  the 
  white 
  tipi)ed 
  over-hairs. 
  Feet 
  

   grayish 
  white. 
  Tail 
  scantily 
  haired, 
  not 
  distinctly 
  blackish 
  above. 
  

   Length, 
  280 
  mm.: 
  tail 
  to 
  end 
  of 
  vertebr;i^, 
  128 
  (to 
  end 
  of 
  hairs, 
  133); 
  

  

  