DIV. I 



THALLOPHYTA 



383 



spore a division may take place, so that two swarm-spores are liberated. In some 

 species the swarm-spores can increase in number by fission. Eventually the 



C 



FIG. 312. Trichia varla. A, Closed and open sporangia (x 6); B, a fibre of the capillitium 

 (x 240); C, spores (x 240). D, Leocarpus fragilis. Groups of sporangia upon a Moss. 

 (Nat. size.) 



cilium is drawn in, and the swarm-spore becomes transformed into a MYXAMOEBA 

 (Fig. 313 i, Tc) ; these have the capacity of multiplication by division (Fig. 314 A, B}. 

 In conditions unfavourable for their development they surround themselves with 

 walls, and as MICROCYSTS pass into a state of rest, from which, under favourable 



FIG. 313. Chondrioder'mu di/orme. a, Dry, shrivelled spore ; b, swollen spore ; c and d, spores 

 showing escaping contents ; e t f, g, swarm-spores ; 7i, swarm-spore changing to a myxamoeba ; 

 i, younger, k, older myxamoebae. Cf. Fig. 4. ( x 540. After STRASBURGER.) 



conditions, they again emerge as swarm - spores. According to JAHN ( 14 ) the 

 myxamoebae fuse in pairs, their haploid nuclei uniting (Fig. 314 C). 



The uninucleate amoeboid zygotes, which have thus resulted from a sexual 

 fusion, unite to_form larger multinucleate plasniodia. These take up additional 



