43§ BOTANICAL GAZETTE [june 



Schmitz (13) , Wolfe (19), and some other workers on the red 

 algae have found that the spermatium is sometimes discharged as 

 a naked protoplast. Svedelius* (14) therefore maintains that a 

 distinction should be made between the free spermatium, the naked 

 protoplast, and this same protoplast inclosed in a cell wall as it is 

 when attached to the parent plant. He refers to the protoplast 

 inclosed in the cell wall as the "spermatangium." The cell which 

 Svedelius refers to as the " spermatangium mother cell" is anal- 

 ogous to the " spermatium mother cell" of Nemalion (Wolfe 19). 



, Spermatium mother cells. — The spermatium mother cells of 

 Dumontia filiformis are homologous to the outer cortical cells of 

 the tetrasporic and cystocarpic plants. In a mature male plant 

 of Dumontia almost all the outer layer of cells of all the branches 

 and of the entire main axis from about 1 cm. above the holdfast 

 consists of spermatia and their mother cells. The outer cortical 

 cells of the main axis just above the holdfast are similar to those 

 of the tetrasporic and cystocarpic plants. Although the distribu- 

 tion and position of the spermatium mother cells on the individuals 

 of the different genera varies considerably, no other form has been 

 reported in which they form a continuous layer over almost the 

 entire thallus as they do in Dumontia. Each stalk cell in Dumontia 

 bears at least two and probably more spermatium mother cells 

 (tig. 15). The spermatium mother cell may bear two spermatia, 

 just as it does in Polysiphonia (Yamanouchi 20), Martensia 

 (Svedelius 14), and Delesseria (Svedelius 16). 



A distinct chromatophore is certainly present in the stalk cell 

 of the spermatium mother cell of Dumontia filiformis (fig. 15)* 

 A chromatophore is occasionally seen at the base of a spermatium 

 mother cell borne on one of these stalk cells. The upper part of 

 such a mother cell contains only granular cytoplasm (fig. 19)- 

 Many of the mother cells contain only cytoplasm and no chromato- 

 phores (fig. 15, first cell to right). Although it was not visible, a 

 net of cytoplasm is undoubtedly present in the stalk cells as it is 

 in all the vegetative cells of Dumontia. When the spermatium 

 mother cell was first formed, it must have contained a chromato- 

 phore which had been cut oflf from that in the stalk cell. A large 

 portion of the granular cytoplasm in the spermatium mother cell 





