46 
MR.  E.  T.  BENNETT  ON  THE  CHINCHILLIDiE. 
ternal,  of  Lagotis,  comparing  it  as  I  proceed  with  the  Chinchilla,  and  occasionally  with 
Lagostornus  also.  My  materials  for  the  description  of  Lagotis  are  derived  from  the  ob- 
servation of  the  living  animal ;  its  anatomical  examination  after  death  ;  and  the  study 
of  its  preserved  skin  and  skeleton,  which  now  form  part  of  the  Society's  Museum.  Of 
Chinchilla  the  Society  has  exhibited,  during  the  last  five  years,  no  fewer  than  four  living 
individuals ;  two  of  which  have  lately  died,  and  have  thus  afforded  me  the  opportu- 
nity of  again  investigating  their  internal  structure,  which  I  had  previously  observed  in 
the  specimen,  also  from  the  Society's  Menagerie,  formerly  dissected  by  Mr.  Yarrell. 
Besides  these  I  have  seen  two  entire  skins  in  the  most  perfect  condition.  My  know- 
ledge of  Lagostornus  is  founded  on  a  detailed  comparison  of  Mr.  Brookes's  account  of 
the  skeleton  of  that  animal  with  the  original  while  in  his  possession,  an  examination 
which  enables  me  to  bear  the  fullest  testimony  to  the  accuracy  of  the  statements  con- 
tained in  his  paper  on  the  subject.  I  shall  begin  with  the  outward  form,  the  peculia- 
rities of  the  fur,  and  its  colouring. 
The  Lagotis  Cuvieri,  or  long-eared  Viscacha,  has  the  size  and  much  of  the  general 
form  of  the  Rabbit.  Its  head  is  of  moderate  size,  broad  at  the  zygomata  and  narrowing 
towards  the  muzzle,  but  considerably  thickened  out  by  the  pads  for  implanting  the  very 
numerous,  closely  set,  and  heavy  whiskers.  These  are  entirely  of  a  jet-black,  and  ten 
or  twelve  of  them  on  each  side  are  exceedingly  strong,  rigid,  and  of  great  length,  the 
longest  when  turned  backwards  projecting  more  than  an  inch  beyond  the  tips  of  the 
ears,  and  measuring  upwards  of  seven  inches  in  length :  they  give  a  striking  character 
to  the  physiognomy  of  the  animal.  There  is  no  naked  muzzle,  the  whole  circumference 
of  the  nostrils,  with  the  exception  of  their  margins  and  an  intervening  slit,  being  covered 
with  short  projecting  hairs.  The  nostrils  are  simple  and  oblique ;  that  is  to  say,  di- 
rected downwards  and  mesiad,  so  as  to  approach  each  other  very  nearly  at  their  lower 
extremities.  In  the  upper  lip  the  fissure  is  so  deep  as  to  correspond  by  its  sinus  to 
the  insertion  of  the  incisor  teeth.  The  eyes  are  not  large,  but  full  and  prominent,  and 
their  anterior  canthus  is  nearly  equidistant  from  the  base  of  the  ears  and  the  extremity 
of  the  muzzle.  The  ears  have  nearly  the  form  of  a  long  parallelogram  regularly  rounded 
at  the  upper  end,  and  equal  in  length  the  distance  between  their  base  and  the  muzzle. 
Their  breadth  is  about  one  third  of  their  length,  the  respective  measurements  being  one 
inch  and  three  inches.  Their  anterior  margin  is  rolled  round  upon  itself,  sloping  in- 
wards from  above  downwards,  and  occupying  at  the  lower  end  more  than  one  third  of 
the  breadth  of  the  base  of  the  ear.  A  corresponding  fold,  extending  at  the  base  to 
about  the  same  distance  inwards,  commences  a  little  lower  down  on  the  hinder  margin. 
Behind  this  there  is  a  supplementary  auricle  accompanying  it  for  two  thirds  of  its 
length.  On  the  outside  the  ears  are  sparingly  furnished  with  short  scattered  hairs,  and 
on  the  inside  still  more  sparingly,  and  with  hairs  still  shorter :  those  which  fringe  the 
margin  are  rather  longer,  particularly  on  the  anterior  edge,  where  they  are  also  more 
copious. 
The  neck  is  short  and  thick,  and  the  body  somewhat  heavy  in  its  proportions ;  or  at 
