ON SAPEOLEGNI.E. 275 



I shall adopt the simple plan of describing what I have seen 

 and drawn, together with methods employed, leaving more 

 general conclusions until afterwards. 



1. Achlya polyandra. — Masses of debris of "meal-worms" 

 on which this species had been grown some months previously, 

 and which had been kept in a cool cellar during the interval, 

 were placed, together with a fresh meal-worm in a large 

 deep glass beaker perfectly clean, with a considerable quantity 

 of boiled and filtered water, and a glass plate over the top; the 

 whole stood in a -well-lighted room at the ordinary (summer) 

 temperature. In the course of two or three days, during 

 which the water was several times replaced, the floating grub 

 was seen to be developing pale, cottony filaments in all direc- 

 tions, on and in the water around. These filaments proved to 

 be slender, straight tubes, filled with hyaline protoplasm in 

 which numerous large granules were scattered, especially in 

 the larger specimens ; the walls became distinctly coloured 

 blue in Schultz's solution, and in H2SO4, after treatment with 

 iodine, the protoplasmic contents becoming yellow in the former 

 reagent. 



After a considerable mass of these radiating tubules had be- 

 come developed, certain of them were found to bear zoospo- 

 rangia. The development of a zoosporange was observed 

 many times in the following manner : — A broad glass slip being 

 placed in the water under the whole growth of Achlya, the 

 attacked meal-worm was lifted up bodily, and transferred to 

 the stage of the microscope ; plenty of water being carefully 

 added to the specimen, the upper, more or less floating 

 branches, could be easily observed with a Zeiss D with a little 

 care. The great advantage of this or a similar method is that 

 the Achlya goes on growing almost undisturbed, and fresh 

 water can be continually added as evaporation goes on. If a 

 higher power is needed, it is very easy to place a small piece 

 of very thin, perfectly dry and clean glass, so as to float on 

 the flooded object, and remove it dexterously afterwards. 

 These very delicate ciyptogams will not grow in a normal man- 

 ner under the pressure of an ordinary cover-slip, if continued, 



