i6 BrannoH. — The Structure and Development of 



In Schmitz's discussion of the origin of the female sexual 

 cells of the Florideae, he states that without exception they 

 develop from the end-cells of shorter or longer side-branches 

 of the whole system of ramification of thallus-filaments ; that 

 these branches are formed sometimes as secondary side- 

 branches subsequently to the formation of other ramifications ; 

 and that, in all cases, the female sexual cell, the carpogonium, 

 is formed from the end-cell of the side-branch by permitting 

 a process to project from its apex which develops into a more 

 or less long hair-like trichogyne. 



As has been shown in the foregoing description of the 

 origin of the procarpium and carpogonium, GrinnelUa agrees 

 with many of the Florideae in the development of these 

 organs. 



It was impossible to discover antherozoids fusing with the 

 trichogynes of freshly collected material, therefore several 

 young female fronds were placed in a dish of water and 

 covered with antheridial plants. The same degree of care 

 was observed with respect to the change of filtered sea-water 

 at stated periods and the excess of light and heat as had been 

 found necessary in the successful germination of spores and 

 the preservation of living GrinnelUa plants. Very satisfactory 

 results followed, and several cases of fusion and partial fusion 

 were found in sections of specimens artificially brought 

 together. 



The carpogonium is fertilized by the fusion of one or more 

 antherozoids with the trichogyne (Fig. 19 a). It was im- 

 possible to identify the nucleus in the antherozoids, and 

 equally difficult to determine whether the trichogyne possessed 

 a nucleus. Hence no union of nuclei was observed when the 

 cell-contents of the antherozoid were intimately associated 

 with those of the trichogyne. In the latter there were 

 individual and grouped particles, which took a deeper stain 

 when treated with Delafield's haematoxylin than the sur- 

 rounding non-granular substance. 



In somewhat older specimens the trichogyne is separated 

 from the fertilized carpogonium by a cellulose plug which is 



