RACES AND RELATIONSHIPS OF HONEY-BEES. 213 



the variability of each generation, and, for the matter of that, of 

 each individual, since modified through altered surroundings, 

 would have left its impression upon the race, and thereby have 

 become inheritable. For this reason reversion can manifest 

 itself only in one or the other predominately aboriginally in- 

 herited direction, whilst, at the same time, newly-acquired 

 characteristics, whether physical or mental, and which perhaps 

 have obliterated others, may remain more or less stable. 



A complete reversion is, therefore, impossible to take place, 

 and what at times becomes observable is only a partial or in- 

 dicated one, which is always modified by later acquisitions. This 

 applies equally to species, geographical races, climatic races, or 

 varieties. It is obvious that the further either of these are 

 removed from the typical ancestor, the more are the physical or 

 mental peculiarities modified, and in like measure the tendency 

 towards reversion will be modified both in character as well as 

 frequency. 



The nearest approach to a complete reversion that is known 

 to me, at least so far as coloration goes, is that of the rabbit, 

 which, as most Australians well know, has in this country 

 assumed, in a comparatively short time, a very uniform greyish 

 fur, as nearly as possible like that of the typical wild European 

 species. But this cannot be solely attributed to the tendency 

 towards reversion, powerful though this tendency happens to be 

 in this animal, but it is greatly assisted by natural selection. In 

 a country like Australia, abounding in birds of prey, those indi- 

 viduals not possessing a protective colouring stand a lesser chance 

 of survival. On the other hand, the reversion is not complete, 

 because the fertility of this pest has enormously increased, which 

 is probably entirely due to climatic influences, since it is found in 

 a near ally — the hare. 



The most surprising reversion known to naturalists is, how- 

 ever, that of the Axolotl — an amphibian belonging to the Sala- 

 mander family, which is found in the Lake of Mexico. This 

 remarkable animal has reverted to nearly the exact condition of 

 the larval stages of other species of this genus, but it is sexually 

 perfect and quite prolific. In this case the reversion has ex- 

 tended to a form that occurs in the genealogy of its evolution, 

 under which it appeared in a former epoch of the earth's history. 



