BRITISH MYCETOZOA. 



13 



Ceratiomyxa, and is characterised by the numerous white spores 

 being borne on the outside of columnar or branching sporophores. 

 These are delicate, fragile structures, often covering two or three 

 square inches of the dead wood on which they grow. The surface 

 of the sporophore is mapped out into polyhedral areolae, from the 

 centre of each of which arises a slender stalk bearing a single 

 ellipsoid spore. On placing the ripe spores in water, the mem- 

 branous spore-wall at once slips off, and the naked contents lie for 

 several hours without apparent change, retaining their ellipsoid 

 form. A constriction then 

 takes place at right angles 

 to the long axis, and before 

 division is completed a 

 second constriction of each 

 half occurs; each of the four 

 lobes thus formed again be- 

 comes constricted, and we 

 have eight globular bodies 

 adhering together and ex- 

 hibiting slow amoeboid move- 

 ment ; each of these bodies 

 now produces a flagellum, 

 and the cluster swims away 

 by aid of the lashing flagella. 

 In a short time the swarm- 

 cells separate, and behave, 

 so far as their history has 

 been traced, in the same 

 manner as those of the 

 Endosporea: The colourless 

 Plasmodium inhabits the sub- 

 stance of rotten wood, and 

 exhibits rhythmic streaming 

 with the same intervals of 

 time between the forward 

 and backward flow as in 

 the larger sub-class of the 

 group. 



The Mycetozoa are remarkably cosmopolitan, a large number 

 of species being found with identically the same characters in 

 Europe, India, the Cape of Good Hope, Australia, and North and 

 South America. 



Of the hundred and seventy-five species which are represented 

 in the British Museum collection, fifty-six have not yet been recorded 

 from this country, and these have chiefly been obtained from the 

 United States and the Tropics. During the last few years about 

 thirty British species have been added to the list given in Cooke's 

 "Myxomycetes of Great Britain," and it is probable that many more 



Fig. 8. — Ceratiomyxa mucida Schroet. 



<7. Spore. 



b. Spore-contents escaping from the spore-wall. 



c to i, 1 . Successive stages in the division of the 



naked spore into eight. 

 /;. Cluster of eight swarm-cells. 



Magnified 1200 times. 



