ACRASIE^. 83 



crowded masses which are very conspicuous on decayed 

 wood, etc., as the chrome-yellow of various species of 

 Trichia, or the vermilion forms of Arcyria. In one group 

 the Plasmodium contains a large quantity of carbofiate of 

 lime, which is deposited in the wall of the sporangium, and 

 also in the capillitium, to such an extent as to render them 

 quite rigid. The spores are as a rule spherical, and either 

 clear yellow or brown with a violet tinge, passing in many 

 species to a clear purple. The wall at first gives a cellulose 

 reaction, and is often ornamented with characteristic mark- 

 ings. In many species the spores are capable of germinating 

 at once, the contents again combining to form a plasmodium. 

 The genus Ceratium, containing twelve species, some of 

 which resemble much branched trees in miniature, differs 

 from all other known Myxomycetes in not having the spores 

 produced in sporangia {endosporous), but free on the outside 

 of the sporophore {exosporous). 



Class II. — Acrasie/e. 



The members of the present group differ from those of 

 the Myxomycetes in never producing ciliated swarm-spores, 

 the amceboid movement being the only one known ; and 

 further, the spores although becoming massed together 

 previous to spore-forrhation, never coalesce to form a 

 Plasmodium as defined above. 



As already stated, the Mycetozoa are considered by De 

 Bary and his followers as lying outside the Vegetable 

 Kingdom, and certainly the whole behaviour during the 

 vegetative phase favours this view. Of course the spon- 

 taneous movements exhibited by the swarm-spores are not 

 supposed to prove their animal nature, as similar motile 

 cells occur in seaweeds, mosses, and ferns. During the 



