1 58 NATURAL HISTORY SOCIETY OF DUBLIN. 



but no such function seems to be confirmed by actual observation. It 

 is, perhaps, more probable that they are homologous rather with the 

 microgonidia of Hydrodictyon, a plant otherwise presenting so very 

 many affinities with Stephanosphaera. Pringsheim has shown that in 

 Hydrodictyon the microgonidia are really structures intended them- 

 selves eventually to reproduce the plant in a future season.* 



It will be seen that Stephanosphsera differs from its well-established 

 fellow-genera in Yolvocinaceae — not to descend to minor but important 

 details of structure and development — from Yolvox, in having the 

 zoospores or primordial cells eight only, and at the equator, not nu- 

 merous all over the periphery of a sphere ; from Pandorina, in having 

 eight only at the equator, not sixteen or thirty-two, arranged in tiers ; 

 from Gonium, in having the eight primordial cells within a common 

 spherical envelope, not sixteen, each having a thick coat, cohering by cer- 

 tain points of their surface into a tablet ; and fromProtococcus (Chlamy- 

 dococcus), by the cells not being solitary. 



Having thus endeavoured to convey an idea of the nature and ap- 

 pearance, of the structure and development of Stephanosphssra, a neces- 

 sary preliminary to the short and very imperfect note I have to offer, I 

 now proceed to draw attention to the peculiar condition which it is 

 meant to record. 



I have mentioned that, at a certain time, the primordial cells, in 

 this organism, having become removed from the inner surface of the 

 common hyaline sphere (envelope-cell) and having acquired a rounded 

 figure, may proceed thereupon to further developmental changes, with 

 the object of directly producing each a new young globe, or may assume 

 temporarily either an intervening Chlamydomonas-like or aProtococcus- 

 like condition. Now, in certain of my specimens the development of 

 the primordial cells had advanced in this direction so far as the draw- 

 ing in of the protoplasmic prolongations, and the assumption of a 

 rounded form, in which condition they sometimes persist for some time 

 when long in the house in a secluded position, the globes still revolving 

 vigorously and actively. But having isolated a considerable number 

 of these examples on a growing-slide, and on my return to them some 

 hours afterwards, I was very greatly astonished to find the slide to a 

 considerable extent crowded by a number of what appeared to me to be 

 Amoebae of some un described species, and these in active movement, 

 gliding about and crossing each other in every direction. These were 

 certainly not to be seen when I last looked at the slide, and the pheno- 

 menon was beyond measure puzzling. I therefore rigidly examined 

 them. It will readily be believed that my astonishment was beyond 

 measure great, upon shortly beyond all question identifying these vigo- 



* " Berichte der Akademie der Wissenschaften zu Berlin," 1860 ; " Ann. des Sciences 

 Naturelles," IV me . Ser., t. xiv., p. 52; "Quart. Journ. of Mic. Sci.," N. S., vol. ii., 

 p. 54. 



