148 Permanence and Evolution. 



without any positive evidence. Somewhat 

 similar views are entertained by Mr. Mivart, 

 " Genesis of Species ; " but much of what he says 

 seems (though intended only against Dar- 

 winism) really to tell against the hypothesis of 

 evolution in any form, while his instances in 

 support of sudden modifications are mostly 

 doubtful. I allude specially to what Mivart 

 says on independent similarities of structure. 

 He specially instances the sub-divisions of Mar- 

 supials corresponding to many of the orders of 

 Placentals (the thylacine to the Carnivores, the 

 kangaroos to the Macroscelides, the wombat 

 to Rodents), which suggested at one time to 

 Huxley the idea that these marsupial sub- 

 orders were the origin from which the placental 

 ones had been developed. If this be true, the 

 characters marking a Placental as distinguished 

 from a Marsupial must have been several times 

 independently developed ; if we take the more 

 common view, viz., that all Placentals and all 



