BRITISH MYCETOZOA. 



The Mycetozoa are a group of organisms which may be placed 

 in the border-land between the Animal and Vegetable Kingdoms. 

 They are characterised by the constant sequence of three main 

 stages in their life history, viz. : — 



1. The firm-walled spore gives birth to a swarm-cell. 



2. The swarm-cells coalesce to form a wandering Plasmodium. 



3. The Plasmodium ultimately concentrates to form either 



sporangia, enclosing numerous spores (Endosporeae), 

 or sporoplwres bearing spores on their outer surface 

 (Exosporeae). 

 Many species are quite common, and are found on old decaying 

 stumps and fallen branches in moist woods and shaded gardens ; 

 others inhabit heaps of dead leaves which have lain undisturbed and 

 become soaked with rain. The only stage in which they are con- 

 spicuous is that of the sporangia, 

 when they appear as minute ob- 

 jects, some roundish, about the size 

 of small mustard seeds, others rising 

 in clusters of brown columns on 

 black hair-like stalks, while many 

 take other characteristic forms. The 

 different species display great vari- 

 ety and beauty in the colours they 

 assume, ranging from pure white, 

 golden yellow, bright crimson, and 

 iridescent violet to dark purple and 

 black. 



The various phases in the life 

 history of the group may be de- 

 scribed as follows : — 



The swarm-cells emerge from 

 the spores as amoeboid bodies ; 

 they soon acquire a flagellum at 

 the anterior end, and creep in a 

 linear form with the flagellum ex- 

 tended in advance, or swim in the 

 surrounding water with a dancing 



DlDYMlUM DIFFORME Duby. 



a. Spore. 



b. Swarm-cell escaping from the spore- 



case. 



c. Newly hatched swarm-cell containing a 



nucleus, and three vacuoles. 



d. Flagellated swarm-cell. 



e. Swarm-cell, with two vacuoles contain- 



ing bacteria, and produced at the pos- 

 terior end into pseudopodia, to one of 

 which a bacterium is attached. 

 /. Amoeboid swarm-cell. 



Magnified 720 times. 



Swarm-cells 



