144 America?! Quarterly Alicroscopical Journal. 



to the oogonium. This antherozoid is then spherical and swims 

 off with a slow, irregular rotation. Three minutes after leaving 

 the sac, and after it has settled down to a state of rest, it 

 gradually assumes an irregular shape, and crawls along the 

 filaments, or on whatever object it has chanced to alight, with 

 a true amoeboid movement, sending out irregular rounded 

 projections in different directions and drawing itself into a 

 simple mass again, being in many of its shapes so precisely 

 like an amoeba that I could hardly believe that they came from 

 the empty sacs seen on the oogonia, until I had watched their 

 development in a number of instances. Several of these an- 

 therozoids ma}'^ be given off from the same oogonium, but 

 never more than one from the same sac ; and since many 

 oogonia are developed at the same time, the water surrounding 

 the filaments swarms with great numbers of the antherozoids, 

 making the chances of fertilization almost certain. I have 

 seen as many as five antherozoids on one oogonium. I have 

 carefully noted the change of an amoeboid body over the sur- 

 face of an oogonium, but as there were presented no very im- 

 portant differences, have only given drawings made at intervals 

 of twenty minutes (Plate VII., Figs. 13 — 18). How long they 

 are capable of continuing this movement I am unable to say, 

 but have noted it in specimens for two hours and a half. When 

 they do not take part in fertilization, they eventually settle 

 down to a spherical form, and are of no further value in the 

 economy of the plant. 



According to M. Cornu (2 PI. II.) the antherozoid in M. 

 spcchrica and Vi. polyinorpha passes through an opening in the 

 top of the oogonium — the only opening present — to effect 

 fertilization, but in M. lateralis the antherozoid sends through 

 one of the many openings a small tube through which the 

 mass of the antherozoid passes, leaving a delicate membrane, 

 but smaller than the antherozoid sac, on the outside. I can- 

 not give the time required for germination after fertilization 

 takes place, but have known it to occur within seven or eight 

 days. These sexual forms have the ppvver of reproducing 

 themselves, for in six experiments, each of which was sown 

 with spores from the one preceding,, and with one exception 

 done before any other forms of fruit were produced, each re- 

 sulted in the development of oogonia. 



It was suggested that these forms might be an aquatic con- 



