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What are Mycetozoa ? 



The Mycetozoa or 'FiiHyn* tuinmds (also known as Myxo- 

 mycetes or Slime Fungi] are Protozoa which, at one stage 

 of their life- history, have the form of a plasmodium. They 

 move slowly by outflowings of the protoplasmic mass, 

 which is often of great size. They are semi-terrestrial 

 and are found in damp situations in humus, on decaying 

 leaves, under bark, in rotting tree-trunks, upon fungi, etc. 

 Their mode of nutrition is both fungus-like (saprophytic) 

 and animal-like (holozoic). In their saprophytic mode of 

 feeding and in their reproduction (by formation of spor- 

 angia and liberation of spores) they show affinity with 

 the lower plants. 



Describe a Plasmodium. 



A naked composite body formed by the mutual attrac- 

 tion, massing together and fusion of a number of amoeboid 

 individuals (plastogamy). Their outward form is lost, 

 but their nuclei remain distinct. 



A plasmodium may, however, be formed by repeated 

 nuclear division without subsequent fusion of the cell- body. 



Write an Account of the Life-history of the Mycetozoa, 



ivilh special reference to Fuligo septic.a. 

 Large plasmodia (of Fuligo), several inches in width and 

 like spreads of slime are often seen upon the oak- bark in 

 tan-yards. Under dry conditions these encrust, passing 

 into the resting state known as the sclerotium ; but with 

 a return of moisture resume activity. The bright yellow 

 plasmodium creeps out. to the light and .air. This is the 

 familiar phenomenon known as " the flowering of the 

 tan-heaps." When about to reproduce, it seeks a dry 

 situation. The protoplasm breaks up into masses, each 

 containing one or more nuclei. These masses encyst. 

 Each cyst has a coat composed largely of lime, and inside 

 there is a network of threads (the capillitium). Division 

 of the contained nuclei is followed by multiple fission, 

 and a number of cellulose-coated spores are thus formed 



