156 THE CASE AGAINST EVOLUTION 



and terminates with its death, and it is reproduction which 

 constitutes the connecting link between one life-cycle and 

 another. 



Reproduction, as previously intimated, is mainly of two 

 kinds, namely: somatogenic reproduction, which is less gen- 

 eral and confined to the metists, and cytogenic reproduction, 

 which is common to metists and protists, and which is the 

 ordinary method by which new organisms originate. Repro- 

 duction is termed somatogenic, when the germ separated from 

 the body of the parent consists of a whole mass of somatic 

 or tissue cells not expressly set aside and specialized for 

 reproductive purposes. Reproduction is termed cytogenic, 

 when the germ separated from the parent or parents consists 

 of a single cell (e.g. a spore, gamete, or zygote) dedicated 

 especially to reproductive purposes. 



Cytogenic reproduction may be either nonsexual (agamic) 

 or sexual, according as the cell which constitutes the germ is 

 an agamete or a gamete. An agamete is a germ cell not 

 specialized for union with another complementary cell, or, 

 in other words, it is a reproductive cell incapable of syngamy, 

 e.g. a spore. A gamete, on the other hand, is a reproductive 

 cell (germ cell) specialized for the production of a zygote 

 (a synthetic or diploid germ cell) by union with a comple- 

 mentary cell, e.g. an egg, or a sperm. 



Nonsexual cytogenic reproduction is of three kinds, ac- 

 cording to the nature of the agamete. When a unicellular 

 organism gives rise to two new individuals by simple cell- 

 division, we have fissiparation or binary fission. When a 

 small cell or bud is formed and separated by division from 

 a larger parent cell, we have budding (gemmation) or un- 

 equal fission. When the nucleus of the parent cell divides 

 many times to form a number of daughter-nuclei, which 

 then partition the cytoplasm of the parent cell among them- 

 selves so as to form a large number of reproductive cells 

 called spores, we have what is known as sporulation or 

 multiple fission. The first and second kind of nonsexual 



