84 N. H. COWDRY. 



degeneration. They are distributed quite evenly throughout the 

 plasmodium which definitely precludes the possibility that they 

 may result from mechanical injury. In preparations stained 

 with fuchsin and methyl green, the small nuclei take the fuchsin 

 to a remarkable degree, behaving just like the nuclei of the spores, 

 which stain in precisely the same way. This points, perhaps, 

 to the conclusion that these small nuclei are undergoing dif- 

 ferentiation with a view to spore formation. 



Sporangium Wall and Hypothallus: 



My observations do not bear upon the question of the mode of 

 formation of the sporangium wall and hypothallus. In all 

 probability both of them are differentiations or secretions of the 

 plasmodium as is generally supposed. I have found no indica- 

 tions that the mitochondria play any part in their formation. 

 They are at first gelatinous and afterwards become membranous. 

 A good account of sporangium formation in Trichia and Arcyria 

 is given by Kranzlin ('07, p. 179). 



With this progressive differentiation of spores, capillitium, 

 sporangium w r all and hypothallus, there is a distinct and gradual 

 alteration in the plasmodium itself. At first it usually contains 

 comparatively large quantities of debris, the more solid portion 

 of which is left behind in its path and persists to some extent 

 in the hypothallus. There is a further segregation with the for- 

 mation of differentiated products, the end result being that the 

 protoplasm of the spores is comparatively free of foreign material. 



DISCUSSION. 



We are inclined to divide living organisms into two groups, 

 plants and animals, and perhaps unconsciously to assume that 

 this classification is sufficient. It is interesting to find that the 

 Myxomycetes, or slime moulds, cannot be dismissed so easily, 

 for they partake of the properties which we have been inclined to 

 regard as distinctive of plants, on the one hand, and of animals, 

 on the other. Great difference of opinion is manifest in the 

 literature. At first they were considered to be plants and were 

 called Myxogastres, in 1829, by Fries, who grouped them among 

 the fungi. The word Myxomycetes also indicates their fungous- 



