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RESEARCHES ON FUNGI 



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Fig. 82. — Dictyostelium mucoroides, one of the Acrasieae. 



A, tiny mucor-like fruit-bodies at the surface of a horse- 

 dung ball (shown in vertical section), natural size. B, a 

 small fruit-body (aboutO- 5 mm. high) on dung-agar, mag- 

 nified 66 times ; the spores are in a naked mass at the top 

 of the sporophore. C, some spores isolated from one 

 another. D, a myxamoeba which has just escaped from a 

 spore. E, myxamoebae, showing vacuoles each con- 

 taining a bacterium. F, a myxamoeba dividing. G, a 

 large number of myxamoebae are swarming together and 

 are forming a collective plasmodium which is becoming 

 heaped up in the centre where it will develop into a fruit- 

 body ; the arrows indicate the direction of movement of 

 the assembling myxamoebae ; the myxamoebae in the 

 Plasmodium, while in contact with one another, retain 

 their identity. H, the collective plasmodium forming 

 a fruit-body, seen in lateral view. I, the interior of a 

 fruit-body at the same stage of development as H ; some 

 of the myxamoebae are forming a sporophore up the 

 centre, and the others are flowing upwards about the 

 sporophore. J, a fully formed fruit-body made up of a 

 sporophore crowned with a mass of naked spores ; the 

 shaft and basal cells of the sporophore are made up of 

 altered myxamoebae which take no direct part in repro- 

 duction, but the sporophore as a wliole serves to place the 

 spores in a favourable position for dissemination by in- 

 sects, etc. K, lower part of a sporophore of a fruit-body 

 larger than J. D and F, after Brefeld ; the rest original, 

 from Winnipeg material. Magnification : A, natural size ; 



B, 66 ; C, E, G-K, 293 ; D, 666 ; F, 300. 



