THE MYCETOZOA. 



143 



flow upwards to higher levels, and send out and again 



withdraw simple or branched processes. Und^r favour- 



able conditions, of moisture 



groups of sporangia are formed 



from the plasmodia with con- 



siderable rapidity, presenting 



the appearance of large pedun- 



culated or sessile bladders, only 



a few millimeters in size. The 



spores fill the interior of the 



ripe sporangium in the form of 



a dusty powder ; they are simple 



roundish cells, with a coloured 



membrane ; when they germi- 



. i n i 



imte they do not send out a cetes (trichia varia) a not 



Fig 1 . 25. Spores of a myxomv- 

 cetes (trichia varia) a not 



germinating tube, but the pro- Xlf Son o"f *& 



toplasm passes OUt of the Spore amoeboid swarming body. 

 , ,, f c (AfterdeBary.) 



membrane in the form of 



swarming spores, which are round or egg-shaped bodies, 

 with a swinging cilium at their anterior end ; at this end 

 of the swarming spore lies a cell nucleus, while the other 

 part contains one or two vacuoles, which alternately con- 

 tract and dilate, and contain watery fluid. The swarming 

 spores sometimes swim freely, rotation round ths axis 

 and side to side movements being caused by the activity 

 of the cilium ; at other times they creep like amosbae, 

 protoplasmic processes being sent out and retracted. 

 The swarming spores multiply by segmentation ; they 

 finally unite together in constantly increasing numbers, 

 and thus form again a plasmodium. 



The acrasice differ from the myxornycetes only in that Tho acrasiee. 

 tli3 swarming spores do not fuse together to form 

 plasmodia, but become closely aggregated and then each 

 forms a spore. 



Themonadina, or the lower mycetozoa, form swarming The monadina. 

 spores, amoebae, plasmodia, and spores in the same way 

 as the higher mycetozoa ; they are distinguished chiefly 

 by the fact that the result of the differentiation of the 

 plasma in the sporangia is the production of reproductive 

 cells in the form of mobile swarming spores or amoebae ; 



