NATURE. NOTES. 113 
Erlenmeyer flasks along with short stalks of hay. The 
flasks were sterilised on three successive days, and were 
then planted with spores of D. nigripes. Zoospores were 
found in them all, but they did not all produce sporangia. 
In some cultures plasmodia crawled up out of the medium, 
preparatory to the formation of sporangia, as early as the 
twelfth day ; in others, not until later. The plasmodium of 
D. nigripes is greyish-white in colour. It consists of the 
usual network of protoplasm, and, in my cultures, extended 
in size from about an inch square to 3 or 4 square inches. It 
advances over the glass with a creeping movement, like a 
gigantic amceba. Under the microscope, the granular proto- 
plasm can be seen to be in constant movement, streaming 
along the veins of the network in a rapid torrent, which 
gradually slows, and, after a slight pause, flows back again 
in the opposite direction. This rhythmic flow forwards and 
backwards generally lasts longer in the direction in which 
the plasmodium is moving. When about to form sporangia, 
it leaves the medium and creeps up the hay or side of the 
flask. Aggregations of the protoplasm take place at certain 
points, forming small, round, darker spots, which rise up into 
small projections, and ultimately form the sporangia. When 
fully formed the sporangia are snow-white, with the stalk a 
yellow-brown, becoming darker lower, and swelling out into 
a broad, dark brown base. The spores are of a pale violet- 
brown colour, and the outside of the sporangium wall is 
covered with stellate crystals of calcium carbonate. 
Both the zoospores and the plasmodia of the Mycetozoa 
may pass into a resting stage and become encysted. Ac- 
cording to Lister, “in all cultivations of germinating spores a 
number of the zoospores become encysted in a globular form. 
They are known as microcysts. The plasmodium in the 
resting stage is known as a sclerotium. The protoplasm 
becomes divided into a number of cysts, and in this state it 
may remain alive for two or three years.” 
A. E. J. Carrer. 
VOL. I. 9 
