26 EVOLUTION. 



Thus retrogression, stability, and progression are all 

 accounted for and harmonize with the theory of 

 Evolution. 



The Axolotl, a Mexican newt or small lizard that 

 retains the early fish gills with the later lungs, when 

 removed to Paris was found to develop into a differ- 

 ent animal, a gill-less newt named Amblystoma, prov- 

 ing the power of changed circumstances to alter the 

 species. This case may be a reversion to an earlier 

 ancestral form. 



Retrogression is shown in parasites. The ship 

 barnacle is at one time a swimming animal with 

 varied organs, but after attaching itself to its life 

 abode it degenerates to a lower form, because in its 

 dependent life the higher development of organs is 

 useless. The horse and mule sometimes have 

 stripes on their legs similar to those of the zebra, 

 suggesting that their ancestors have had that pecul- 

 iarity. In Madeira two hundred out of over five 

 hundred species of beetles " are so deficient in wings 

 that they cannot fly." The beedes that fiew well 

 were blown out to sea, but those with smaller wings, 

 or that were indolent, remained and perpetuated 

 their peculiarities, the wings growing smaller from 

 disuse. 



Men and women sometimes show reversion to the 

 forms of animals, such as hairy bodies, supplement- 

 ary breasts, and animal teeth ; one man in sixty has 

 certain muscles peculiar to quadrupeds, and muscles 



