54 PROTOMYXA AND THE MYCETOZOA 



other substance : and as they do so ingest solid food 

 (Fig. 7, A). It has been proved that they digest protoplasm : 

 and in one genus pepsin the constituent of our own gastric 

 juice by which the digestion of proteids is effected (see p. 12) 

 -has been found to exist. They can also digest starch 

 which has been swollen by a moderate heatas in our own 

 bread and rice-puddings but are unable to make use of 

 raw starch. 



After living in this free condition, like a gigantic terrestrial 

 Amoeba, for a longer or shorter time, either a part or the 

 whole of the protoplasm becomes encysted 1 and breaks up 

 into spores. These (B) consist of a globular mass of proto- 

 plasm covered with a wall of cellulose : the cysts are also 

 formed of cellulose. 



By the rupture of the cell-wall of the spore (c) the protoplasm 

 is liberated as a flagellula (D) provided with a nucleus and a 

 contractile vacuole, and frequently exhibiting amoeboid as 

 well as ciliary movements. After a time the flagellulse lose 

 their cilia and pass into the condition of amcebulae (E), 

 which finally fuse to form the plasmodium with which 

 we started (F H). In the young plasmodia (c 1 ) the 

 nuclei of the constituent amcebulje are clearly visible, and 

 from them the nuclei of the fully developed plasmodia are 

 probably derived. It would seem, therefore, that in the 

 fusion of amcebulae to form the plasmodium of Mycetozoa the 

 cell-bodies (protoplasm) only coalesce, not the nuclei. 



There is a suggestive analogy between this process of 

 plasmodium-formation and that of conjugation as seen in 

 Heteromita. Two Heteromitoe fuse and form a zygote the 



1 The process of formation of the cyst or sporangium is a compli- 

 cated one, and will not be described here. See De Bary, Fungi, 

 Mycetozoa, and Bacteria (Oxford, 1887). 



