joz 



from t}ae "beginning identica,!. The tetrasporic pla-nt of a 

 red alga may "be said, tlien, to be homolocous v/ith the sex- 

 ual plant. 



That the tv/o phases are homologous is evidenced, not 

 only by their similarity of structtire, but b;^ the fa,ct that 

 either seems capable of producing the morphological equiv- 

 alent of the reproductive structiires of the other. It has 

 been known since BOroiRT first called attention to the fact 

 ( ) that in many species of red algae structures re- 

 sembling tetraspores are occasionally found on the sexual 

 individuals. This phenomenon has been carefully investi- 

 gated in Polrsiphonia violacea and Griff ithsia 3ornet_iana. 

 In Polysiphonia , YA:IA:T0TJCHI ('06b) found that the develop- 

 ment of these tetraspore-like structures ceases at the moth- 

 er cell stage; cleavage of the cytoplasm ma;' begin, but 

 noi-Tiial nuclesir division is absent. In Griff ithsia , the 

 phenomena observed h< ve been similaj? to those noted in 

 Polysiphonia^ , e:;cept that by the time tlie abortive cleavage 

 begins, the nacleus has divided into two or three. The 

 cleavage planes have never been observed to reach the cen- 

 tre of the cell, and it is quite evident that tetraspores 

 are not formed, since the v/liole cell becomes withered and 

 wrinkled, resembling the degenero ted tetrasporangia de- 



