Numerous cases could be given of striking resemblances in quite distinct beings between single parts or organs, which have been adapted for the same functions.

A good instance is afforded by the close resemblance of the jaws of the dog and Tasmanian wolf or Thylacinus--animals which are widely sundered in the natural system.

But this resemblance is confined to general appearance, as in the prominence of the canines, and in the cutting shape of the molar teeth.