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MR.  R.  OWEN  ON  THE  YOUNG  OF 
At  the  time  when  I  was  engaged  in  examining  the  structure  and  relations  of  the 
mammary  glands  of  the  Ornithorhynchus  in  1832,  my  friend  Mr.  George  Bennett  was 
frequently  with  me  :  he  became  deeply  interested  in  the  question,  and  left  England  for 
Australia,  determined  on  devoting  his  utmost  endeavours  while  in  that  country  towards 
its  solution.  His  efforts  have  been  attended  with  unexampled  success,  especially  when 
it  is  considered  how  short  a  space  of  time  was  allowed  him  for  these  investigations.  The 
results  of  his  observations  on  the  habits  and  economy  of  the  Ornithorhynchus,  he  will 
himself  lay  before  the  Society  ;  and  I  shall  only  here  allude  to  a  few  of  the  facts  which 
relate  more  immediately  to  the  subject  of  the  present  communication. 
The  season  of  copulation  is  at  the  latter  end  of  September  or  the  beginning  of  the 
month  of  October.  The  precise  period  of  gestation,  and  the  condition  of  the  excluded 
product,  still  remain  to  be  determined ;  but  in  the  first  week  in  December  Mr.  G.  Ben- 
nett found  in  one  of  the  nests  of  the  Ornithorhynchus,  three  ^  small  naked  embryos,  not 
quite  two  inches  in  length,  and  which  he  therefore  supposes,  with  much  probability,  to 
have  been  recently  born.  These  specimens  he  was  unable  to  preserve,  from  the  want  of 
the  necessary  means  in  a  situation  remote  from  any  settlement. 
Fortunately,  young  specimens  of  Ornithorhynchus  a  little  further  advanced  have  been 
transmitted  through  other  channels  to  this  country.  The  Society  is  indebted  for  them 
to  the  prompt  liberality  of  Dr.  Hume  Weatherhead,  and  they  form  the  subject  of  the 
present  communication.  These  specimens  are  of  different  sizes  :  the  smaller  one  rather 
exceeds  2  inches  in  length,  measured  from  the  end  of  the  bill  to  the  end  of  the  tail  in 
a  straight  line  ;  the  larger  one  is  double  that  size,  and  is  one  of  those  two  young  ani- 
mals which,  with  the  mother,  were  taken  from  a  nest  on  the  banks  of  the  Fish  River, 
and  kept  alive  for  about  a  fortnight  by  Lieut,  the  Hon.  Lauderdale  Maule^. 
The  following  are  admeasurements  of  these  two  specimens. 
Smaller  Orni- 
thorhynchus. 
Length  from  the  end  of  the  upper  jaw  over  the  curve  of  inches.  Lines. 
the  back  to  the  end  of  the  tail  3  9 
Length  from  the  same  points  in  a  straight  line  along  the 
abdomen  2  1 
Greatest  circumference  of  the  body  2  9 
Length  of  the  head  
Length  of  the  upper  mandible   3 
Breadth  of  the  upper  mandible  at  the  base   4 
Thickness  of  the  upper  mandible  at  the  anterior  margin  . 
Length  of  the  lower  mandible   2 
'  The  left  ovary  of  one  of  the  impregnated  uteri  exhibited  three  corpora  lutea,  and  Mr,  G.  Bennett  believes 
that  the  Ornithorhynchus  occasionally  brings  forth  four  young  ones. 
*  Proceedings  of  the  Committee  of  Science,  Zool.  Soc.,  vol.  ii.  p.  45. 
Larger  Orni- 
thorhynchus. 
Inches.  Lines. 
6  6 
4  0 
4  8 
1  0 
5 
6 
1 
24- 
