Similarly in the third volume of his On the Anatomy of Vertebrates (1868) while discussing fossil series of perissodactyls Owen wrote: If the alternative ??????species by miracle or by law? ??????be applied to Pal??otherium, Palopotherium, Anchitherium, Hipparion, Equus, I accept the latter, without misgiving, and recognise such law as continuously operative throughout tertiary time. (Owen 1868, p