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MR.  E.  T.  BENNETT  ON  THE  CHINCHILLID^. 
Lagotis,  an  inch  and  a  half  in  length,  with  a  breadth  of  an  inch  at  its  lower  extremity. 
The  latter  part  was  broader  in  proportion  in  Chinchilla,  the  corresponding  measurements 
being  one  inch,  and  seven-eighths  of  an  inch.  The  kidneys  were  of  the  usual  form,  the 
right  considerably  higher  than  the  left ;  the  tubuli  uriniferi  terminating,  as  in  most  Ro- 
dentia,  in  a  single  conical  papilla :  they  measured,  in  Chinchilla,  nearly  three  quarters 
of  an  inch  in  length  by  half  an  inch  in  breadth.  The  renal  capsules  were  oblong  white 
bodies,  lying  mesiad  of  the  upper  part  of  the  kidneys,  and  measuring  in  Chinchilla 
nearly  half  an  inch  in  length.  In  Lagotis,  the  omentum,  which  was  of  moderate  size, 
as  well  as  the  mesentery,  contained  fat ;  but  this  was  wanting  in  Chinchilla,  the  indi- 
vidual having  died  most  probably  of  a  deficiency  of  nutriment,  in  consequence  of  an 
inability  to  masticate  its  food  from  the  incisor  teeth  of  the  upper  jaw  having  become 
excessively  elongated  and  incurved,  as  happens  not  unfrequently  in  rabbits,  rats,  and 
other  Rodentia. 
In  Lagotis  the  urinary  bladder  was  large,  a  good  deal  distended,  and  contained  a 
firm,  gritty,  coagulated  substance  of  a  white  colour,  which  Mr,  Owen  conjectured 
might  possibly  be  formed  by  inspissated  semen  thrown  back  into  it.  The  plexus  pam- 
piniformis  and  spermatic  omenta  were  well-developed ;  and  the  vasa  deferentia  were 
large.  The  vesiculcB  seminales  formed  tubes  of  three  inches  in  length,  giving  off  nu- 
merous coeca  from  one  side.  The  testes  were  of  the  size  of  pigeon's  eggs,  and  the  fibres 
derived  from  the  transversalis  muscle,  adhering  to  the  upper  part  of  the  epididymis, 
formed  a  sheath  from  which  its  extremity  projected  into  the  inguen.  The  prostate 
gland  was  large  and  lobed  ;  and  the  penis  furnished  with  a  bone.  Both  the  Chinchillas, 
as  well  as  that  previously  examined  by  Mr.  Yarrell,  were  females :  their  organs  pre- 
sented little  that  was  remarkable.  The  cornua  uteri  measured  three  inches  and  a  half 
in  length. 
On  opening  the  thorax  of  Lagotis,  the  heart  was  seen  to  be  nearly  quadrate  in  its 
form,  with  obscurely  rounded  angles ;  in  Chinchilla  it  was  more  elongated  and  more 
rounded  at  the  apex.  The  two  superior  vence  cava  were  distinct.  The  lungs  on  the  left 
side  were  divided  into  three  lobes,  of  which  the  lowest  was  the  largest ;  and  on  the 
right  into  four,  with  the  lowest  also  largest,  and  in  Chinchilla  deeply  bifid.  The  section 
of  the  trachea  was  transversely  oval,  with  the  rings  imperfect  behind.  The  tongue,  in 
both  animals,  was  broad  at  the  base,  becoming  narrower  anterior  to  the  molar  teeth, 
from  which  point  it  was  continued  forwards  nearly  of  the  same  breadth.  It  was  rather 
flattened,  and  rounded  at  the  extremity ;  its  surface  being  finely  papillose,  except 
between  the  molar  teeth,  where  it  was  smooth.  Behind  this  part  were  two  large  oblong 
papillcE  fossulatee,  disposed  obliquely,  with  their  posterior  extremities  directed  inwards 
and  towards  the  epiglottis. 
My  friend  Mr.  Owen,  to  whom  I  was  indebted  for  assistance  in  the  dissection  of 
Lagotis,  and  who  has  since  examined  another  specimen  of  Chinchilla  from  the  Society's 
Collection,  has  favoured  me  with  his  notes,  in  which  he  gives  a  much  greater  length 
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