﻿small 
  Mammals 
  from 
  Djarl-ent. 
  571 
  

  

  fuscicepa, 
  of 
  which 
  I 
  originally 
  described 
  this 
  Ellohius 
  as 
  a 
  

   subspecies. 
  

  

  In 
  E.fuscipes 
  the 
  lanibdoid 
  ridge 
  is 
  continuous 
  and 
  well 
  

   defined 
  right 
  across 
  the 
  skull, 
  bowed 
  forwards 
  in 
  its 
  middle 
  

   third. 
  In 
  ursulus 
  it 
  is 
  practically 
  obsolete 
  for 
  tliis 
  middle 
  

   third, 
  tlie 
  crown 
  and 
  occipital 
  areas 
  passing 
  almost 
  smoothly 
  

   into 
  one 
  another. 
  In 
  ursutus, 
  also, 
  m^ 
  tends 
  to 
  be 
  rather 
  

   simpler 
  than 
  in 
  fusciceps. 
  

  

  29. 
  Allactaga 
  rilchheili, 
  sp. 
  n. 
  

  

  Six. 
  - 
  

  

  A. 
  mongoJica 
  group. 
  

  

  Size 
  about 
  as 
  in 
  A. 
  suschklni 
  and 
  mongolica, 
  larger 
  than 
  

   in 
  saltalor. 
  Colour 
  rather 
  paler 
  than 
  in 
  our 
  examples 
  

   of 
  sahator. 
  Crown 
  distinctly 
  greyer 
  than 
  back. 
  Ears 
  

   proportionally 
  long, 
  apparently 
  about 
  as 
  long 
  as 
  in 
  susch- 
  

   kini. 
  Hands 
  and 
  feet 
  pure 
  white 
  ; 
  central 
  sole-pad 
  un- 
  

   covered 
  in 
  all 
  the 
  specimens^ 
  cohered 
  with 
  hair 
  in 
  all 
  the 
  

   available 
  examples 
  of 
  mongoUca 
  and 
  saltator. 
  Tail 
  bufFy 
  

   above, 
  white 
  below, 
  with 
  well-marked 
  white 
  ring 
  before 
  the 
  

   black 
  one, 
  black 
  ring 
  varying 
  from 
  about 
  45 
  to 
  55 
  mm., 
  

   measured 
  from 
  its 
  commencement 
  in 
  the 
  middle 
  line 
  to 
  the 
  

   tips 
  of 
  the 
  longest 
  hairs; 
  white 
  terminal 
  tufts 
  short, 
  only 
  

   about 
  30-35 
  mm. 
  measured 
  in 
  the 
  same 
  way. 
  

  

  Skull 
  larger 
  than 
  in 
  saltator, 
  with 
  shorter 
  muzzle 
  than 
  in 
  

   mongolica. 
  

  

  Dimensions 
  of 
  the 
  type 
  : 
  — 
  

  

  Head 
  and 
  body 
  150 
  mm. 
  ; 
  tail 
  220; 
  hind 
  foot 
  (s. 
  u.) 
  7G 
  ; 
  

   ear 
  49. 
  

  

  Skull: 
  greatest 
  length, 
  occiput 
  to 
  gnathion, 
  39; 
  condylo- 
  

   incisive 
  length 
  38"3 
  ; 
  zygomatic 
  breadth 
  25*8 
  ; 
  nasals 
  14'3 
  x 
  

   6; 
  interorbital 
  breadth 
  10"8 
  ; 
  breadth 
  of 
  brain-case 
  19; 
  pala- 
  

   tilar 
  length 
  22*5 
  ; 
  palatal 
  foramina 
  8*7 
  ; 
  molar 
  series 
  (exclu- 
  

   sive 
  of 
  premolar) 
  6*3. 
  

  

  Type. 
  Adult 
  female. 
  B.M. 
  no. 
  14. 
  5. 
  10. 
  203. 
  Original 
  

   number 
  247. 
  Collected 
  6th 
  April, 
  19J3. 
  

  

  " 
  On 
  banks 
  of 
  River 
  Uszek." 
  

  

  This 
  jerboa 
  is 
  probably 
  most 
  nearly 
  allied 
  to 
  A. 
  suschJcini, 
  

   from 
  north 
  of 
  the 
  Aral 
  Sea, 
  but 
  is 
  distinguished 
  by 
  having 
  

   a 
  well-marked 
  white 
  ring 
  before 
  the 
  black 
  one 
  of 
  the 
  tail, 
  no 
  

   trace 
  of 
  such 
  a 
  ring 
  being 
  present 
  in 
  suschkini, 
  and, 
  on 
  tiie 
  

   other 
  hand, 
  by 
  its 
  very 
  much 
  shorter 
  white 
  terminal 
  tuft. 
  

   From 
  A, 
  saltator 
  it 
  is 
  distinguished 
  by 
  its 
  larger 
  size 
  and 
  

   the 
  more 
  open 
  condition 
  of 
  the 
  foot-pads. 
  Mr 
  Hollister's 
  

   A. 
  grisescens, 
  coming 
  not 
  only 
  from 
  the 
  general 
  region, 
  but 
  

  

  