280  A  DINOSAURIAN  VERTEBRA  FROM  HASTINGS.  [May  1893. 
caudal  vertebrae  known  as  those  of  Cetiosaurus  brevis.  There  was  no 
principle  of  correlation  which  could  infer  a  generic  type  of  humerus 
from  the  tail.  In  the  same  way,  there  is  no  evidence  at  present 
from  association  of  specimens  which  would  justify  reference  of  the 
tooth  named  Hojplosaurus  to  any  of  the  other  Wealden  remains  :  it 
is  a  type  of  tooth  which  shows  but  little  modification  in  allied 
animals.  And  therefore  it  seemed  to  him  safer  not  to  assume 
knowledge,  when  the  evidence  did  not  prove  the  nature  of  the  rest 
of  the  skeleton.  With  regard  to  the  vertebrae  named  Ornithopsis , 
he  had  long  been  prepared  to  find  that  the  Wealden  vertebrae, 
originally  described  from  Tilgate,  might  belong  to  a  different 
species  from  the  Isle  of  Wight  type;  because  he  believed  that 
few,  if  any,  of  the  species  of  fossil  reptiles  are  common  to  these 
two  Wealden  areas.  He  had  not  yet  seen  evidence  of  generic 
difference ;  and  he  thought  that  weight  was  to  be  attached  to 
the  Author’s  suggestion  that  the  new  vertebra  from  Tilgate  came 
from  a  vertebral  region  not  previously  known.  There  was  no 
means  of  showing  that  these  vertebrae  could  be  associated  with  the 
remains  referred  to  the  other  genera  discussed.  It  therefore 
seemed  to  him  that  the  future  progress  of  science  required  that 
these  genera  should  be  kept  separate.  Future  discoveries  may 
enable  some  of  them  to  be  put  together;  but  if  that  was  to  be 
done  hereafter,  great  caution  was  required  so  as  not  to  attempt 
formulating  conclusions  beyond  the  limits  of  knowledge. 
Mr.  E.  T.  Newton  acknowledged  the  desirability  of  uniting 
under  one  name  parts  of  skeletons  which  had  been  differently 
named,  when  there  was  reasonable  evidence  of  their  belonging 
to  one  form ;  but  he  pointed  out  the  necessity  of  caution  in  this 
matter,  lest  the  troubles  of  nomenclature  should  be  increased 
rather  than  diminished. 
The  Author  replied,  maintaining  his  conclusions. 
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