14 The Mycetozoa, and 



are common in both the great kingdoms of organized life. 

 There is a whole group of protoplasts which, under the 

 name of Monads, are reckoned to belong to the animal 

 kingdom ; there is the group of somewhat larger organisms 

 known as " AmoeboB " a group of which a suspicion has 

 sometimes been entertained that they are an immature form 

 of other organisms ; there are the white particles of the 

 blood which are almost, if not quite undistinguishable 

 from Amcebce ; there are the swarm spores, whether 

 belonging to the Algae, the Fungi, or the Myxomycetes; in 

 all these cases the protoplasts are of the same kind, 

 endowed with nuclei and vacuoles, capable of putting out 

 cilia, and endowed with the power of motion and assimila- 

 tion. To all appearances there is no essential difference 

 between them, and yet, in point of fact, they are organisms 

 as distinct as possible from one another hi their nature and 

 their future careers. 



One thing marks off the swarm spores of the myxies 

 from all other swarm spores which reproduce the organism ; 

 they are reproductive only in conjunction. The swarm 

 spore of an alga is capable by itself of reproducing an alga ; 

 in the myxies, on the other hand, the swarm spores only 

 reproduce when they have merged with their fellows and 

 formed a plasmodium. This phenomenon of the union of 

 a large number of individual swarm spores into a new and 

 larger individual which carries forward the course of life 

 is unique in the myxies, and distinguishes them broadly 

 from all other known organisms. 



In all cases in which reproduction depends on swarm 



