ZOOLOGY AND BOTANY, MICROSCOPYj ETC. 397 



of old spores thickens and becomes brown ; tbey often contain a large 

 central vacuole or some oil-drops. Chains of spores or fragments of 

 mycelium are found among them when in situ. When cultivated in a 

 detached fragment of infected sponge beneath a watch-glass, the 

 spores germinate, producing either chains of spores or a mycelium, 

 the ramifications of which produce simple or branched strings of 

 young spores by successive budding (by which the terminal spore is 

 always the youngest). The terminal spore not unfrequently gives rise 

 to a mycelium-thread. The fungus has also been cultivated upon 

 gelatine. The reason why it occurs in dense masses on particular 

 parts of an infected sponge appears to be that at such points occur 

 the masses of bacterian zoogloea and remains of sponge-sarcocle, which 

 in point of fact are almost always to be found on damp sponges, and 

 that these present favourable localities for the growth of the fungus. 

 Experiments tend to show the presence of soap to be rather unfavour- 

 able than otherwise to this organism. From the history of the plant 

 it is easy to understand how one sponge infects another. To cure 

 affected sponges they should be soaked for some hours in somewhat 

 strong solutions of carbolic or salicylic acid, or treated with boiling 

 water. 



Glycogen in the Mucorini.* — In continuation of his observations 

 on the presence of glycogen in various plants,! L. Errera now finds it 

 in all the Mucorini which he has examined. 



In Phycomyces nitens it occurs in the mycelium, fertile filaments, 

 and young sporangia ; it appears to pervade the protoplasm, and not 

 to be locally aggregated, as is usually the case in the asci of the 

 Ascomycetes. Its abundance varies in different parts of the cell. 

 When Phycomyces is subjected to the action of strong alcohol, the 

 protoplasm contracts, and expels the glycogen, which then distributes 

 itself through the cell- sap, and can be detected by iodine. In very 

 young filaments the glycogen is distributed through the whole proto- 

 plasm, but is most abundant in the apical region of the cell ; and this 

 is especially the case at the moment when the sporangium is about to 

 be formed. It does not diminish during the formation of the sporan- 

 gium ; and when this is definitely constituted, but before the separa- 

 tion of the spores, it is very rich in glycogen, and but little remains 

 in the filament. In the formation of the spores it is taken up chiefly 

 by their protoplasmic contents, and not by their cell-wall. It is 

 possible that a certain quantity of glycogen is required for the respi- 

 ratory combustion of Phycomyces, and by the growth of the cell- 

 wall of the filament, sporangium, and spores ; but the greater part is 

 taken up by the protoplasmic contents of the spores ; it probably 

 exists there partly in the form of glycogen, while a portion is trans- 

 formed into other substances. 



Mucor Mucedo and stolonifer also contain glycogen, but in smaller 

 quantities than Phycomyces, and it is more difficult of detection. Its 

 distribution through the filaments at different stages corresponds to 



* Bull. Acad. R. Sci. Belg., 11. (1882) pp. 451-7. 

 t See this Journal, ii. (1882) p. 824. 



