RHODOPHYCE.E, OR FLORIDE.E 205 



there are formed carpospore-beanng fruits ; or the 

 carpogonium conjugates with an auxiliary cell by 

 means of a long or short (generally short) ooblastema 

 filament, and the auxiliary cell then gives rise to the 

 carpospore-bearing fruits. This remarkable and 

 unique power of handing on the fertilising influence 

 from the carpogonium which receives it to other 

 (auxiliary) cells, which then behave like fertilised 

 cells, is of great interest, since it appears to be with- 

 out a parallel in nature. The filaments, gonimoblasts, 

 which bear the carpospores always spring from 

 fertilised cells, and the carpospore fruits may be either 

 borne free or within special capsules, or immersed 

 within the thallus, according to the group. 



Non-sexual reproduction is effected by motionless 

 spores called tetrasporcs, from their usual occurrence 

 in fours within a sporangium. However, one only or 

 two are formed in some cases ; and the arrangement 

 of the fours is a variable one. When all four spores 

 are formed simultaneously they present together the 

 form of a tetrad (Fig. 61, a) ; but when they are formed 

 by successive bipartitions, two different types arise. 

 If in the second division the walls are parallel to the 

 first one formed, the result is a series of four spores, one 

 above the other, called zonate tetraspores (Fig. 61, c). 

 If the two secondary walls are not parallel, but 

 perpendicular to the first formed, .and not in one 

 plane with each other, but at an angle of 90, the 

 result is the arrangement called cruciate tetraspores 

 (Fig. 61, &). The tetraspores occur externally, and 

 also within the cortical layers of the thallus. In 

 some cases they occur in large numbers on definite 



