ANIMAL LIFE GENERATION. 339 



cells of an infus-orian often seem to couple 

 though they are just alike as far as can be 

 seen. Then dimorphism appears in which 

 two different cells are observed to conjugate 

 for reproduction. The so-called parthen- 

 ogenesis is single generation (or uni-paren- 

 tal), but some biologists claim that it is a de- 

 generate reproduction from sexual cells, hence 

 a lapse. Undoubtedly single Generation 

 (monogenetic) is most common in the lower 

 animals, such as the worms and ccelenterates, 

 while it is lacking in the higher orders. More- 

 over, as the animal rises' in the scale, there 

 takes place a differentiation between the 

 body-cell and the sex-cell, which act also 

 shows a gradation. The cells of Generation 

 become differenced from those of Assimila- 

 tion, and are stored up in their own special 

 organ. The animal which is still in a vegetal 

 stage is propagated by budding; its tissues or 

 its cells must possess both kinds of reproduc- 

 tion, assimilative and generative; it is still 

 a plant-animal (phytozoon). Outer bodily 

 growth can turn into a new individual, which 

 fact indicates a low, or vegetal, or purely as- 

 similative stage of the animal organism, not 

 yet evolved to the fully generative stage. 

 "When the animal is practically all stomach, 

 procreation is a product of digestion the 

 generative principle has not yet developed 



