MR.  E.  T.  BENNETT  ON  THE  CHINCHILLIDiE. 
63 
Kerodon,  and  Dolichotis,)  were  absolutely  unknown,  in  a  zoological  sense,  only  twelve 
years  ago.  Two  of  these,  Chinchilla  and  Lagotis,  were  first  fully  described  from  speci- 
mens contained  in  the  Menagerie  and  Museum  of  this  Society  ;  of  a  third,  Octodon,  the 
only  account  yet  extant  is  derived  from  the  same  source ;  and  to  the  history  of  two 
others,  Capromys  and  Ctenodactylus,  most  important  additions  have  been  made  from 
the  examination  of  individuals  formerly  living  in  our  Gardens. 
In  a  department  which  has  afforded,  during  so  short  a  period,  so  many  additions  to 
science,  it  is  reasonable  to  anticipate,  and  probably  for  many  years  to  come,  repeated 
and  almost  continual  accessions.  In  various  parts  of  the  world  which  are  comparatively 
well  known,  the  Rodentia  are  far  from  being  exhausted  as  objects  of  zoological  inquiry  ; 
and  the  vast  continents  of  Africa  and  America  (the  latter,  especially  in  its  southern 
half,  apparently  the  metropohs  of  the  order,)  have  hitherto,  perhaps,  furnished  us  with 
only  a  foretaste  of  what  may  be  expected  from  them,  when  their  interior  shall  be  opened 
to  the  investigations  of  active  and  informed  travellers.  To  the  materials  which  will 
doubtless  be  collected  by  the  zeal  and  enterprise  of  such  men  we  must  look  for  the 
means  of  correcting  and  completing  the  confessedly  imperfect  sketch  of  the  Herbivorous 
portion  of  the  order,  which  I  have  ventured  to  submit  to  the  consideration  of  the 
Society. 
PLATE  IV. 
Lagotis  Cuvieri. 
PLATE  V. 
Fig.  1.  Stomach  of  Lagotis  Cuvieri. 
2.  CcEcum  of  Lagotis  Cuvieri. 
3.  Stomach  of  Chinchilla  lanigera. 
4.  CcBcum  of  Chinchilla  lanigera,  less  distended  than  that  of  Lagotis. 
PLATE  VI. 
Skeleton  of  Lagotis  Cuvieri,  two-thirds  of  the  natural  size. 
Fig.  1.  Cranium  seen  from  above. 
2.  Cranium  seen  from  below. 
3.  Lower  jaw  seen  from  above. 
4.  Crowns  of  the  two  anterior  molar  teeth  of  the  lower  jaw,  enlarged. 
5.  Crowns  of  the  two  posterior  molar  teeth  of  the  upper  jaw,  enlarged. 
