l88 CALIFORNIA ACADEMY OF SCIF:NCES. 



with care, the young prothallium surrounded only by the 

 transparent endospore, may be liberated; but it is so 

 delicate, and the walls are so swollen by this process, 

 that the study of their arrangement is exceedingly dif- 

 ficult, and it was found necessary to devise some means 

 by which the spores could be sectioned. This was finally 

 accomplished by taking the whole sorus and imbedding 

 it. Of course, b}- so doing it is impossible to regulate 

 the direction in which the sections are made, but the 

 number of spores is so great, that some of them are al- 

 most certain to show satisfactorily the desired stages. 



Occupying the center of the spore is a large and dis- 

 tinct globular nucleus. Usually one or more nucleoli are 

 present, and the chromatin seems to be fairly abundant. 

 The cytoplasm shows a more or less reticulate arrange- 

 ment, as if there were large vaculoles which are dis- 

 tributed pretty uniformly throughout the spore. Granules 

 of various sorts are abundant, some of them, especially 

 near the periphery, being the large starch granules al- 

 ready referred to. the others being apparently of albumi- 

 nous nature (pi. iii, fig. 4). 



The first divisions occur under proper conditions in 

 about an hour after the spores are placed in water. Pre- 

 vious to this the nucleus enlarges somewhat and passes 

 to one side, usually the side opposite the apex, and the 

 granules of the protoplasm accumulate near the center 

 of the spore, leaving a more or less clearly defined zone 

 in which the granules are much less numerous. The 

 central granular mass, however, has running from it lines 

 of granules extending to the periphery of the spore (pi. 

 Ill, fig. 7). 



The first wall divides the spore into two very unequal 

 cells, the smaller containing but little granular contents, 

 and representing the vegetative part of the prothallium. 



