]0Z. 



succeeds a sexual individual of identical morrhology. This 

 latter condition is not paralleled in tlie Archegoniate se- 

 ries; and since the terms gametophyte and sporophyte hiave 

 come to have a special significance in connection with such 

 conditions as are found in the Archegoniates , neither of 

 these terms should he applied to the tetra.sporic plants of 

 Griff ithsia and Polysiphonia . The tetra-sporic plant iias 

 prohahly been intercalated in the life history of the red 

 algae, hut there is no evidence for t}ie helief that it lias 

 been intercalated hy gradual integration and differentia- 

 tion of a. simple product of the germination of the zygote, 

 which product was at first unlike the sexua,l plant and 

 which represents a new departure in the life history; and 

 the interco.lation of an unlike phase seems to he the very 

 pith of the theory of antithetic alternation (see B0Y7ER- 

 89-91) . 



According to this view, the tetrasporic plant probably 

 arose, when first produced, v/ith tlie complete differentia- 

 tion characteristic of tlie species. Tlie best evidence for 

 this conclusion is based on tlie morphological identity of 

 the tetra.sporic with the sexual plant. Similar environ- 

 mental conditions would hardly suffice to produce identity 

 of form in two individuals unless the individuals were 



