10 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 82 



in two of the jars, putting instead of the aquarium water, water from 

 beyond the Breakwater which I had in a bottle. 



Today six individuals have passed through the reproductive phase 

 and all have pursued the second course — giving rise to young megalo- 

 spheric individuals. Those (4) in which the protoplasm separated in 

 the afternoon have already (9:35 p.m.) added a second chamber 

 to the megalosphere, while those which have separated since 7 o'clock 

 consist only of a spherical body, with abundant ray-like pseudopodia. 



These six individuals pursued the course described above up to 

 the end of stage iii — the most noticeable feature about them being the 

 large area covered by the protoplasm in the second and third stages — 

 filling the area of the halo. 



This clears up the process in a most satisfactory manner.^ 



To the abstract of the above given in his later works he merely 

 adds : " The whole of the protoplasm of the parent is used up in 

 the formation of the brood of young, the shell being left empty. The 

 process from the first appearance of the halo to the dispersal of the 



young is complete in about 12 hours Each of the spheres was, 



in fact, a megalosphere. The microspheric parent has given rise to, 

 indeed it has become, a brood of megalospheric young." 



Lister was an expert micro-photographer, and in April, 1895, 

 he obtained fresh material from Plymouth, and repeated his obser- 

 vations in his own laboratory, at Cambridge. He heads his notes : 

 " Polystomella material started in dishes, April 30. Several micro- 

 spheric individuals have reproduced in the manner seen at Plymouth 

 last summer. In a few cases the fusion has occurred, but many have 

 formed normal young." His observations, like those of 1894, were 

 made by the " hanging drop " method in the use of which he was 

 an expert. His notes at this time relate to the flagellispore method 

 of reproduction by the megalospheric specimens, but from May 22 

 to 24 he made a wonderful series of micro-photographs, 24 in number 

 from a single microspheric individual of which 15 were made into 

 lantern slides, which slides Mrs. Lister has presented to our collection. 

 A selection of these together with certain of the photographs (which 

 are now being published for the first time) are now available, for all 

 time, for the use of students of Protozoology. Li all, 20 photographs 

 are here reproduced. They may be tabulated as follows : 



^ On July 25 he writes " There is reason to beheve that the aquarium water 

 is affected by the asphalt Hning of the tanks." He tested this with further 

 Polystomellae on the 26th in " outside water " between 8 : 30 a. m. and 7 p. m. 

 with brilHantly successful results. His notes on Polystomella cease, for this 

 time, here. 



1 



