NOTES AND MEMORANDA. 207 



interpretation is that always after their exit the mother- 

 organism — which before was poor in pseudopodia — sent out 

 pseudopodia copiously. 



To the foregoing notes on Acanthocystis the author adds 

 some observations made on Actinophrys Sol. He noticed in 

 a certain large example, that its contents were formed of 

 minute organisms, in extremely vivacious swarming move- 

 ment, so numerous that the alveolar parenchyma had become 

 almost obliterated, leaving only traces in the form of 

 bridge-like connections, reaching between the outer mem- 

 brane-like attenuated cortex and the protoplasmic invest- 

 ment of the nucleus. The nucleus was unchanged, the 

 pseudopodia sparing and short, and without their granular 

 investment, that is, naked axile threads. After some time 

 the cortex burst at various places, and there issued forth 

 many swarms of extremely minute flagellate organisms, about 

 0*004 mm. long, 0"002 mm. broad. Appertaining to each of 

 these bodies, which were capable of amceboid alterations of 

 form, the author was able to perceive two flagella, but could 

 not determine if there were a nucleus and contractile vacuoles 

 present. These soon became scattered about, and the author 

 was unable to follow them any further. The parent Actino- 

 phrys, on emptying out the zoospores, contracted in mass, 

 forming at last a considerably smaller but ordinary looking 

 example. 



The author compares this observation to that of GreefF on 

 Actinosphcerimn Eichhornii already recapitulated in this 

 Journal.! Hertwig seems to be of opinion that both were 

 cases of parasitism, for in Greeff 's case the parent Actino- 

 sphaerium was dead (killed by the parasite ?), and in both 

 instances he supposes the ' amoeboid ' condition of the zoo- 

 spores renders it improbable they could truly belong to the 

 development of an organism which in its natural state 

 possesses pointed pseudopodia. 



To the two observations alluded to, Hertwig might have 

 added the cursory one by myself, recorded in " Minutes of 

 the Dublin Microscopical Club," of the gradual giving off, 

 from that beautiful and large green form, (of A. Sol ?) 

 of but a few zoospores at a time, and so slowly that the loss 

 to the mass of the parent Actinophrys was scarcely appreci- 

 able. Each of these carried off one or two of the chlorophyll- 

 granules. They did not in the least present the appearance 

 or suggest themselves as having the nature of parasites. Nor 

 would it occur to me to suppose that an ' amoeboid ' state in 

 youth of the zoospores was incompatible with a form at 

 * ' Quart. Journ. Micr. Sci.,' vol. xvi, p. 301, 



