DA^IPINTr OFF FUNGUS AND ALLIED FORMS. 233 



formed chiefly as enlargements of the terminal portion of the 

 lateral branches. Each of these is separated by a septum from 

 the hypha supporting it. There are usually in each case tAvo 

 septa, cutting off two cells from the main branch. The terminal 

 one of these becomes spherical and forms the oogonium ; the 

 proximal cell gives off a secondary branch -which results, in a single 

 antheridium. [Figs. 1 and 2, a.] The oogonia, however, are not 

 confined to this terminal position. It is frequently the case that 

 a portion of the filament, anywhere along its length, becomes 

 separated from the remainder by two^ septa, and becomes an 

 oogonium. [Fig. 3.] The oogonia are 20-26/^ in diameter. 

 Each contains one oospore which measures 16-20/*. The oospores 

 have two walls, (1) the exosporium, quite thick {2-2^f^), and (2) 

 the eudosporium, pi-esenting only a single contour. In the early 

 stages of the formation of the oospore, spherules of protoplasm 

 segregate in a manner verj' similar to the condition seen in the 

 formation of zoospores. [Fig. 2.] These masses are variable 

 in size and number, and flow together again at a later stage. In 

 addition to the oogonia and antheridia, there are other terminal 

 swellings which are somewhat smaller (12-15/^), each of Avhich 

 forms a tube in ji manner entireW similar to that described by 

 Hesse and others as the commencement of the formation of 

 zoospores. According to Hesse's description, the protoplasm of 

 the sporangium passes through this tube into a thin- walled en- 

 largement at the end, where the separation into zoospores takes 

 place. I regard the structures represented in Fig. 4 as being 

 zoosporangia, although I have not succeeded as yet in procuring 

 functional zoospores from them. There are other enlargements of 

 the hypha which must be considered purely vegetative. They are 

 short portions of the filament which are cut off by two septa from 

 the remainder, as in the case of the non-terminal oogonia ; but 

 they are not accompanied by antheridia. [Fig. 5.] 



The oospores germinate b}' the rupture of the thick exosporium 

 and the protrusion of a tube from the endosporium. The exten- 

 sion of this tube results immediately in the normal hypha? of the 

 plant. [Fig. 6.] 



The character and position of the zoosporangia, the mouosporous 

 oogonia, the measurements of oogonia and oospores, and the 

 very ramose mycelium seem to indicate that the plant is the 



