MONOTREMES. 295 



ill the placental series : the temporal bono generally presents a permanent separation of the 

 squamous, petrous and tymjjanic elements. And Professor Owen observed this condition of the 

 bone in the mature skulls of an ursine Dasyure, a Virginian Opossum, a Pcramelcs, in different 

 species of Potoroo (or Kangaroo Rats), and Kangaroo, in the Wombat and the Kaola. These 

 characters are fully more reptilian than ornithic, although some of them are shared by both, and 

 other characters leading in a similar direction could easily be cited. 



The sense of our feebleness and inability to follow up the indications which such affinities 

 suggest oppresses us, and makes us, with greater and greater humility, the more we study them, 

 acknowledge that " such knowledge is too wonderful for us ; it is high, we cannot attain unto it." 



