THE MYXOMYCETES 



287 



They hang for a time on the threads of the capillitium, 

 which acts as a supporting scaffolding, and are gradually 

 scattered. The spores can be kept for an unlimited 

 time dry, and germinate readily when wetted (see Fig. 

 116, from another Myxomycete). The membrane splits, 

 and the whole contents become free. The protoplasmic 

 mass at first shows " amreboid " movements, changing its 

 form by putting out and 

 again withdrawing pseu- 

 dopodia. After a few 

 minutes a single cilium 

 is developed at one end, 

 and now the pear-shaped 

 swarm - spore is fully 

 formed (Fig. 116, d). It 

 contains one nucleus, 

 placed near the thin end, 

 and its protoplasm is 

 vacuolated ; one of the 

 vacuoles is contractile, 

 expanding and contract- 

 ing at regular intervals. 

 The swarm-spore swims 

 through the water with 

 a dancing movement, 

 or it creeps along the 

 surface of any solid body like a snail. 



These swarm-spores, like the plasmodia, can take in 

 their food in the solid state. They catch minute objects 

 in the water by means of pseudopodia put out at the 

 broad posterior end. They are particularly fond of 

 Bacteria, which are often caught in this way, the 

 pseudopodia laying hold of the microbe, and in spite of 



FIG. 116. Didymium difforme. , 

 spore ; b, swarm-cell escaping from 

 the spore - membrane ; c, newly - 

 hatched swarm -cell, containing a 

 nucleus and three vacuoles ; d, 

 ciliated swarm-cell ; e, swarm-cell, 

 with two vacuoles containing bacteria 

 another bacterium is just caught 

 by the pseudopodia ; /, amoeboid 

 swarm-cell. Magnified 720. (From 

 Lister's Monograph of the My cetozoa. ) 



