284 



PART IV. CLASSIFICATION. 



elastic capillitium. In many cases the sporangium has a stalk, 

 (sporophore) which is sometimes continued into the cavity of the 

 sporangium as a columella. 



In the Exosporese the spores are not formed in the interior of 

 a sporangium, but by abstriction from the ends of filaments de- 

 veloped from the surface of the sporophore. 



In some forms (e.g. Fuligo vdridns) a compound sporangium is 



II 



Fie. 164J A Part of a plasmodium of ZKdt/mium leucopu* (x 300). J? A closed sporangium 

 of Arcyria incarmito. C The same after the rupture of its wall (p) and expansion of the 

 capillitium cp ( x 20) . (After SachsO 



formed, termed ^Ethalium, by the combination of a number of 

 plasmodia. 



The sporangium : wall and capillitium give the reactions of 

 cuticularised cell-wall. 



The life-history, as sketched above, varies somewhat in different 

 forms'. In some (e.g. Dictyosteliacese, Gruttulinese) the mastigopod 

 stage is wanting; the spores" giving rise directly to amoebae. 

 Again, the mastigo pods' or the amoebae may surround themselves 



