636 Annals of the South African Museum. 



APPENDIX. 



OOSPORE CULTURES, V. Rousseletii. 



Very rich sexual material containing many colonies red with 

 ripening oospores was obtained from one of Mr. Steer's tubs early 

 in February 1931. Some of this was put in an old battery jar half 

 full of water, and placed in a south window. The female colonies 

 disintegrated, and the oospores and detritus collected at the bottom 

 of the jar as a red-brown sediment, most of the detritus eventually 

 being destroyed by the animal organisms present. 



Some of this oospore material was left in the jar, some was placed 

 on slides and allowed to dry. 



Culture I. 



5th July. Material from the stock jar, containing unaltered oospores 

 and spores escaped from their exospores, was transferred to a 

 small vessel to which strained water from the Wetton Road vlei 

 was added. It was placed on soil in a basin of water and put 

 where it would get the morning sun. 



6th July, 6 p.m. Examined ; many oospores with exospore cracked 

 and spores escaping, and golden-brown spores already free from 

 exospore. 



7.45 p.m. Examination continued. Found (1) golden-brown 

 germ colony, 40 x 44 p,, moving inside a delicate vesicle 

 58 x 60 /u,, (2) spore with endospore protruding and contents 

 partly in it, mesospore still enclosed in spiny exospore (see 

 Plate XL VI, H). 



9.20 p.m. Germ colony still dark brown, but clearer ; cilia 

 much longer, very active. A second colony, recently inverted, 

 with very short cilia. 



1th July. Again put in sun during morning. Paramoecium eating 

 many of the smooth-walled spores which had escaped from the 

 spiny outer coat. 



Wi July. Two more germ colonies seen rotating in vesicle ; this 

 time, attached to the vesicle-wall, two long, motionless cilia were 

 clearly visible. Count of cells round the edge 34, 36, giving a 

 cell number of 395 to 471, i.e. intermediate between 2 8 and 2 9 

 (Plate XL VII, G). 



Culture II. 



Oospore material from stock jar transferred to a small dish and 

 allowed to dry out completely. 



3rd August (Monday). Water added as soon as dry, placed in sun 

 as in first culture. Wednesday to Friday, wet and overcast ; 

 Saturday afternoon and Sunday, warm and sunny. 

 August (Sunday). Many small Juveniles present, ranging in size 

 from 53 x 53 ju in vesicle 66 /x and 44 x 66 n (free) to 80 x 80 /z, 

 very active, gonidia 1 to 4. 



