INTRODUCTORY 7 



in others, it doubtless contributes mechanically to the support 

 of the peridial wall, and renders so far persistent the delicate 

 sporangium. For more exact description the reader is again 

 referred to the specific delineations which follow. 



The transition from phase to phase requires, as intimated, 

 no great length of time. Tilmadoche gyrocepliala completed 

 the transition from vegetative to fruiting phase in less than 

 eighteen hours. 



The germination of the spores ensues closely upon their 

 dispersal or maturity and is unique in many respects. The 

 wall of the spore is ruptured and the protoplasmic content 

 escapes as a zoospore indistinguishable so far from an amoeba, 

 or from the zoospore of our Chytridiaceous fungi. This 

 amoeboid zoospore is without cell wall, changes its outline, 

 and moves slowly by creeping or flowing from point to point. 

 At this stage many of the spores assume each a flagellate 

 cilium, and so acquire power of more rapid locomotion. The 

 zoospores, whether ciliate or not, thus enjoy independent 

 existence and are capable of continuing such existence for 

 some time, assimilating, growing, and even reproducing them- 

 selves by simple fission, over and over again. This takes 

 place, of course, only in the presence of suitable nutrient 

 media. Nevertheless the spores of many species germinate 

 quickly simply in water. A drop suspended in the form of 

 the ordinary drop culture on a cover-glass affords ample oppor- 

 tunity. In the course of time, usually not more than two or 

 three days, the swarm spores cease their activity, lose their 

 cilia, and come to rest, exhibiting at most nothing more than 

 the slow amoeboid movement first referred to. In the course 

 of two or three days more, the little spores begin to assemble 

 and flow together; at first into small aggregations, then 

 larger, until at length all have blended in one large creeping 

 protoplasmic mass to form thus once again the plasmodium, 

 or plasmodial phase with which the round began. Small 

 plasmodia may generally be obtained artificially from drop 

 cultures. Such, however, in the experience of the writer, are 



