210 THE BOTANICAL MAGAZINE. [Voi. xxxv. No. 4i9. 



Spepmatium. 



By repeated divisions of vegetative cells in the peripheral portion 

 of thallus, the antheridia or " spermatium mother cells " are formed, 

 which are distinguished from the vegetative cells by the small 

 dimension of cells and in the lighter colour of chromatophore in sur- 

 face view. The antheridial cell is first divided into two with the 

 dividing plane parallel to the surface of thallus. Another plane is 

 formed perpendicular to the first one and divides eaeh cell into two 

 equal daughter cells. The third dividing plane intersects at right 

 angles to the both planes already formed. Thus the octant stage is 

 attained. The unclear divisions preceding these processes take place 

 in the manner typical for all vegetative cells and the divided nuclei 

 which move to the peripheral portion of the cell are always located 

 symmetrically to the new partition wall (Fig. 4, 5). Each octant 

 cell divides three times in the same manner as just described, form- 

 ing a mass of eight cells (Pig. 6, 7), which are sometimes divided 

 once more. Each antheridium thus gives rise to 64 or sometimes 

 128 cells. The ultimate cells become spermatia which are set free in 

 succession. The spermatium is colourless, globular and naked, measur- 

 ing 2.5— 4/i in diameter in average ; in living state the minute structure 

 is difficult to observe. The chromatophore is faintly stained with 

 haematoxylin, but when treated with acid fuchsin it takes light red 

 colour and the pyrenoid is also brightly coloured. In the preparation 

 treated with haematoxylin the nucleus is found as a group of three 

 black points which may be regarded as chromosomes (Fig. 8) ; the 

 nucleus seems to be not in the resting condition as in the most 

 cases of Rhodophyceae so far studied by several writers. Such cases 

 are reported in Polysiphonia (14), Rhodomela (5 b), Delesseria (11a), 

 Nemalion (2), Scinaia (lib), Griffithsia (5 c), Bonnemaisonia (5 d) and 

 Batrachospermum (5 e). Joffe (4) lias figured the nucleus of the 

 matured spermatium as a comparatively large black spot which has 

 nearly the same dimension as that of the carpogonium. That is not 

 the case with Porphyra tenera. 



Carpogonium and Carpospore. 



Carpogonial areas arise from some vegetative cells in the marginal 

 portion of thallus. The carpogonium is generally ellipsoid or ovoid, 

 mostly slightly prominent at one or both ends ; when prominent at 



