220 PRIMARY FACTORS OF ORGANIC EVOLUTION. 



different from a monad. The flagellum is early lost, 

 and the cell is then termed an amcebula, since it does 

 not differ materially from an amoeba. Its movements 

 are similar, and it puts forth short pseudopodia. When 

 these amcebulae come in contact with each other they 



Fig. 54. Mycetozoa (from Lankester after Du Bary). 1-6, Germination 

 of spore (i) of Tricheavaria, showing the emerging flagellula ; (4-5) and its 

 conversion into an amcebula (6). 7-18, Series leading from spore to plasmo- 

 dium phase of Chondrioderma. dijfforma ; 7, spore ; 10, flagellula ; 12, amoe- 

 bula ; 14, apposition of two amcebulae ; 15-17, fusions; 18, plasmodium. 19- 

 20, Spore-fruit (cyst) of Physarum leucoph&um X 25 ; the former from the sur- 

 face, the latter in section with the spores removed to show the sustentacular 

 network or capillitium. 21, Section of the spore-cyst of Dydymium squamulo- 

 sum, with the spores removed to show the radiating capillitium x, and the 

 stalk. 



fuse, often in large numbers, forming a continuous 

 gelatinous sheet, the plasmodium (Fig. 54), which 

 may have several square inches, and even feet of sur- 

 face. At the proper time reproductive organs form 

 on this surface in the form of capsules (sporangia), 

 which may or may not be supported on peduncles, and 



