105 



coast of Helgoland, "Kapselfrflchte, Vierlinf:sfrQchte ,i'nd 

 Anther idi en normal ztisazmnen auf denselben Exemplaren auf- 

 treten" ('61, p. 26). V/hatever may te the conditions in 

 Poly^iphonia and Griff ithsia , in which tetraspore-like 

 structures occuj? only occasionally on the sexiial plants, it 

 seems highly unlikely that such a careful v/orker as PRIITGJ- 

 I-Q-IIM should have mstsJcen for tetraspores structiires vrliich 

 really never "became separated as tetra,spores . Assuming, 

 then, that the structures descri"bed "by PRIIJGSHEIM were 

 really normal tetraspores, it becomes at once evident that 

 differentiation into homologous successive sexual a.nd asex- 

 ual p}iases has not "been "brought about in all Florideae 

 above the ITemalionales, but only in those in which the tet- 

 raspores and sexus-1 organs are borne on distinct plants. 

 Cytological investigation of such a form as Spermothamnion 

 roseolum is much to be desired. 



The theory o^ homologous alternation in the red algae 

 outlined above is almost identical with the viev; of PRIITGE- 

 KRIM as to the relations within this group (»76). PRIITGSR 

 HEIM states (p. 897) "die Annahme ist nachstliegende dass 

 bel Plorideen und Dictyoteen zwischen Exemplaren mit Kap- 

 selfruchten und Exemplaren init Vierlingsfruchten eine Ab- 

 wechselung besteht". PRU'IGSIIEIM'S view was based, however. 



