144 Transactions of the Society. 



■cracks formed by the crushing mills when the oak bark was broken 

 down. 



A stained specimen shows within the hyaline, pellicle-like 

 walls an immense number of granules, some nuclei of various sizes, 

 and some other bodies, the nature of which is not yet determined. 

 These latter stain as deeply as nuclei, but appear to differ from 

 them in many respects. 



Plasmodicaiy. — AAlien fully fed or otherwise mature the Plas- 

 modium aggregates into a semi-globular, extended, or branched 

 mass, in this process extruding the foreign or food-material still 

 ingested, and becomes pure waxy-white (fig. 11); this final form 

 is taken rapidly, and, except for shrinkage on ripening, determines 

 the shape of the plasmodicarp. 



In my cultivations the time occupied in this change is about 

 four or five days — for little over two days the colour remains white, 

 then a tint of yellow, which gradually deepens to a golden yellow, 

 the shining surface of the immature white plasmodium becoming 

 somewhat wrinkled and pitted at maturity (fig. 12). I find that 

 the change of colour is an indication that at least some part of 

 the plasma has formed spores — as these ripen the colour deepens. 

 The white inclosing membrane of the young plasmodicarp is 

 surprisingly tough, the yellow wall when mature comparatively 

 brittle ; it is two layers thick, the outer easily ruptured, the inner 

 thin, membranous, and cellular ; the photograph (No. 19), part of 

 the wall of a mature plasmodicarp, shows what was a revela- 

 tion to me, as to the extent cell -formation takes place in the 

 Mycetozoa. Fig. 15 is from material from an immature plas- 

 modicarp immediately before formation of spores, the strands of 

 protoplasm connecting the nucleus with the peripheral parts, in- 

 dicating a very active condition of the cell contents. In another 

 part of the same preparation nuclear division by mitosis is taking 

 place ; the stages shown are found in one field of a -^^ objective 

 <fig. 16). 



Contents of Plasmodicarp. — The plasmodicarp walls inclose a 

 large number of spores, a capillitium in the form of elaters, and 

 some unused material, as apparently a waste or redundant product. 



Elaters. — The elaters (fig. 14) are yellow, branched, curved, and 

 tube-like, with ring thickenings at irregular distances. Strasburger* 

 has determined that in Trichia fallax the elaters are formed by the 

 aggregation of a number of very minute microsomes ; a smear pre- 

 paration of C. serpula shows a similar mode of formation of its 

 ■elaters. It is assumed that the function of the elaters is to 

 assist in the rupture of the walls, and in the distribution of the 

 spores ; the diameter of the tubular part being about 3 fx, and of 

 the ring enlargements about 4-5 jm. The elaters arise in the plasma 

 as elongated, branching threads (fig. 17), having the appearance in 



• Bot. Zeit., xlii. (1884) p. 305. 



