48 
MR.  E.  T.  BENNETT  ON  THE  CHINCHILLID^. 
little  of  the  dusky  colour  of  the  fur  visible  on  the  under  surface.  The  hairs  of  the  tail 
below  are  entirely  of  a  brownish  black  ;  on  the  sides  they  are  of  two  kinds,  black  and 
white  ;  as  is  also  the  case  with  the  long,  rigid,  and  erectile  hairs  of  the  upper  surface. 
The  very  long  bristly  hairs  of  the  tip  are  wholly  black.  On  the  upper  and  fore  part  of 
the  head  and  face,  as  well  as  on  the  limbs,  the  hair  becomes  much  shorter  than  on  the 
body. 
In  form  the  Chinchilla  nearly  resembles  the  Lagotis  ;  but  it  is  much  smaller  in  size, 
more  slender  in  its  limbs,  with  shorter  and  more  rounded  ears,  and  whiskers  less  nu- 
merous, shorter,  and  less  rigid.  They  are  of  two  kinds,  black  and  white,  some  few 
being  black  in  the  lower  half  and  white  in  the  upper  :  the  longest  measure  about  four 
inches.  The  face  and  muzzle  are  very  similar  to  those  of  Lagotis  ;  but  the  large  rounded 
open  ears  measure  in  height  little  more  than  three  fourths  of  the  distance  between  their 
base  and  the  extremity  of  the  muzzle ;  their  sides  have  none  of  the  parallelism  so  re- 
markable in  Lagotis ;  and  their  greatest  breadth  is  little  inferior  to  their  length,  or 
about  an  inch  and  three  eighths  to  an  inch  and  three  quarters.  In  their  lobes  and 
mode  of  folding  they  differ  in  no  material  respect  from  Lagotis,  and  they  are  as  scantily 
supplied  with  hair  both  within  and  without.  The  tail  has  precisely  the  same  character, 
arising  from  short  rigid  adpressed  hairs  below,  and  long  stiff  erectile  hairs  on  the  upper 
surface,  the  latter  projecting  at  the  tip  in  a  bristly  tuft  which  exceeds  the  vertebra  by 
two  inches. 
The  anterior  and  posterior  limbs  have  nearly  the  same  relative  proportions  to  each 
other  as  those  of  Lagotis  ;  but  the  former  have  an  additional  toe,  corresponding  to  the 
thumb,  which  is  entirely  wanting  in  Lagotis,  and  this  forms  a  striking  part  of  the 
generic  distinction  between  the  two  animals.  The  corresponding  toes  are  similar  in 
their  proportions  to  those  of  Lagotis,  but  slenderer,  and  of  greater  comparative  length 
in  their  free  extent.  On  the  anterior  feet  the  thumb  is  much  shorter  than  the  rest,  its 
extremity  ranging  nearly  its  own  free  length  behind  the  base  of  the  adjoining  toe.  The 
claws  are  small,  flattened,  ridged  along  the  middle  line,  terminating  in  an  obtuse  point, 
and  concealed  by  long  bristly  hairs  ;  that  of  the  thumb  is  less  strongly  ridged  than  the 
rest.  In  the  palm  the  basal  tubercles  nearly  resemble  those  of  Lagotis ;  and  the  three 
which  are  placed  at  the  base  of  the  four  outer  toes  form  a  curved  line,  the  posterior 
extremities  of  which  are  nearly  equally  advanced.  On  the  under  surface  the  skin  is 
deeply  marked  with  strong  transverse  callous  wrinkles,  and  each  toe  is  furnished  with 
a  large  cushion  beneath  its  tip.  The  posterior  feet  have  larger  claws  than  the  anterior, 
but  nearly  of  the  same  form,  and  equally  concealed  by  long  hairs,  with  the  exception 
of  the  inner,  which  in  form  and  in  the  bristly  comb-like  appendage  adjoining  it,  closely 
resembles  that  of  Lagotis.  The  tubercles  of  the  sole  are  disposed  as  in  the  latter  animal ; 
and  the  under  surface  of  the  toes  is  the  same  in  every  respect  as  in  the  fore  feet. 
The  beautiful  fur  of  the  Chinchilla  is  still  more  soft  and  downy  than  that  of  the 
Lagotis,  having  fewer  of  the  long  black  hairs  passing  through  it  and  projecting  beyond 
