424 A. E5. HILTON ON THE STUDY OF THE MYCETOZOA. 



simply pieces of protoplasm, each with a single nucleus and two 

 or three vacuoL s. These jelly-specks, or swarm-cells, as they are 

 called, assume, first, an amoeboid form, and then a shape re- 

 sembling tbigellate infusoria, free-swimming, with a jerky, 

 dancing motion, and feeding on bacteria. Presently, numbers of 

 these -warm -cells, after a process of multiplication by encystment 

 and division, coalesce into a larger jelly-mass, called a plasmodium ; 

 and it is this characteristic which is peculiar to the Mycetozoa, 

 distinguishing them from all other groups of organisms with 

 which they might otherwise be classified. The plasmodium, after 

 slowly creeping about, in or upon decaying vegetable substances, 

 and increasing in bulk by the ingestion of whatever suitable 

 pabulum it meets, ultimately comes to a standstill, concentrates 

 its energies, and throws up sporangia, which form and scatter a 

 new generation of spores, to commence the life-history afresh. 

 The process is varied in different species, and there are further 

 cell-divisions and resting-stages at certain times ; but this may be 

 taken as an approximate general description of the life- cycle, 

 without, for the moment, going into details. 



The evolution of the ideas concerning these organisms is 



reflected in the names by which they have been known. At first 



they were cautiously named Myxogastres — i.e. slime-stomachs — 



doubtless in reference to the plasmodia merely ; but afterwards, 



for a long period, they were more pronouncedly called Myxomy- 



cetes, slime-mushrooms or slime-fungi, thus taking into account 



both the plasmodial and sporangial stages. They were then 



commonly classified with the Gasteromycetous Fungi, as though 



their vegetable nature were indisputable ; but about fifty years 



ago a closer acquaintance with the swarm-cells caused them to be 



renamed Mycetozoa, mushroom-like or fungus-like animals, in 



recognition of relations with low forms of animal life. A 



variation of these ideas was expressed by the name Myxothallo- 



phyta, meaning slime-frond or slime-branch plants ; possibly in 



allusion to the frond-like or branching forms, sometimes assumed 



by the creeping plasmodia. That name, however, has died out ; 



and until the true nature of the organisms is finally determined, 



the correct name cannot be fixed. Even the name Mycetozoa, 



fungus-like animals, must be regarded as distinctive, to distinguish 



thcni from vegetables, rather than as descriptive, to include them 



in the animal kingdom. The difficulty of grouping them properly 



along with other organisms is so great, that it has even been 



suggested that we may have to divide nature into four kiDgdoms 



