MVX O MYCE TES. 2/7 



from the margin of ihe plasmodium, which increase by the protoplasm flowing 

 into them from behind. These arms or branches coalesce laterally, anastomose, and 

 form new projecting arms. When this has proceeded for a considerable time in 

 the same direction, the whole plasmodium is found to have changed its position. 

 In addition smaller tentacle-like arms, into which the inner granular protoplasmic 

 substance does not penetrate, are also put out and again drawn in from the 

 outside. Finally a streaming motion takes place in the interior of the larger 

 arms or of the plate-Hke expansions of the plasmodium, the direction of which 

 is constantly changing. The motile substance in the interior is granular and 

 more watery; but the circumference of the plasmodium is formed of a hyaline 

 layer (the marginal layer) destitute of granules and apparently denser, which is 

 sometimes also surrounded by a layer of mucilage ; this latter is not protoplasm, 

 and is left behind during the creeping like the slime of a snail. 



The greater number of plasmodia are colourless, many yellow (as jEthaliiim 

 septiciwi) or reddish yellow ; some are very small, scarcely visible to the naked eye, 

 others, when mature, attain a size of some square inches, and those of ^thaliiun 

 septiciwi sometimes collect on the surface of the tan into masses the size of the 

 hand or larger, and one-half to one inch thick ; and, in this state, may form 

 spherical or Clavaria-like upright bodies, which however consist of soft cream- 

 like protoplasm. In this condition the ^Ethalium is able to creep away from the 

 tan upon plants even several feet high, and accumulate above on the leaves. 



The Plasmodia take up hard foreign substances which they enclose ; and 

 De Bary supposes that they obtain food in this way. The quantity of the ab- 

 sorbed materials seems, however, too small for this purpose ; the residue of them 

 are afterwards again expelled, especially when the plasmodium passes over into 

 the cellular condition. 



The swarm-spores may, under unfavourable conditions, be again transformed 

 into cells, surrounding themselves with a cell- wall {Microcysts), When dry they 

 remain in this state for months in a vital condition, and when placed in water 

 revert to the motile form. Young plasmodia form, under similar conditions, ' solid- 

 walled cysts,' dividing themselves into pieces of unequal size which become rounded 

 off and surrounded by cell-walls. When the weather is moist and warm the 

 Plasmodium again creeps out of these cysts. The mature plasmodia finally arrive 

 at a state of rest, forming bodies which De Bary calls Scleroiia, when the tempe- 

 rature and amount of moisture decrease. The plasmodium first of all draws in 

 its arms and forms a sieve-like plate or mass of small irregular nodules, and the 

 whole substance breaks up into a large number of roundish or polyhedral cells 

 4V to -jV mm. in diameter. The body thus formed is wax-like, gritty and dry. 

 When placed in water the cell-walls again become absorbed, and the sclerotium 

 reverts to the condition of a motile plasmodium. 



When the mature plasmodia have lived for some time and been in motion 

 on the surface of the substratum, they assume a firmer consistency, and after the 

 net-like mass has collected, it either forms a cake, as in ^Ethalium, or puts forth 

 outgrowths directed upwards, but always soft, of the form of the future sporangia. 

 A firm membrane is formed on the outside, the capillitium and the spores in the 

 inside. If the plasmodium contains lime, it is deposited in the form of granules 



