Organic Evolution. 223 



reproduction during an otherwise immature condition, 

 extreme instances of acceleration. The axolotl habitually 

 reproduces in the gilled, or immature condition. Some 

 species of insects reproduce before they complete their 

 metamorphoses. And the females of certain beetles (Phen- 

 godini) are described by Professor Kiley as larviform.* 



Precocity is variation in the direction of acceleration, 

 and that condensed development which is familiar in the 

 embryos of so many of the higher animals may be regarded 

 as the result of variations constantly tending in the same 

 direction. That there are fewer examples of retardation 

 is probably due to the fact that nature has constantly 

 favoured those that can do the same work equally well in 

 a shorter time than their neighbours. But there can be 

 no doubt that, accompanying that fosterage and protection 

 which is of such marked import in the higher animals, 

 there is also much retardation. And as bearing upon the 

 supposed law of variation as formulated by Messrs. Hyatt 

 and Cope, it should be noted that this retardation or 

 decreased rate of growth leads to the production of the 

 more advanced descendant. 



The Inheritance of Variations. 



Given the occurrence of variations in certain individuals 

 of a species, we have the alternative logical possibilities 

 of their being inherited or their not being inherited. The 

 latter alternative seems at first sight to be in contradiction 

 to the law of persistence. Sir Henry Holland, seeing this, 

 remarked that the real subject of surprise is, not that a 

 character should be inherited, but that any should ever 

 fail to be inherited.! Intercrossing may diminish a 

 character, and sooner or later practically obliterate it : 

 annihilate it at once and in the first generation it cannot. 

 This logical view, however, ceases to be binding if we admit, 



* Nature, vol. xxxvi. p. 592. 



f Quoted from " Medical Notes and Reflections," 1855, p. 267, by Darwiu, 

 " Animals and Plants under Domestication," vol. i. p. 416. 



