136 MYCETOZOA. 



sporangia contain deposits of calcium carbonate, the other without 

 such deposits. Immediately after taking form the sporangia of the 

 division in which the calcareous granules are present in the 

 plasmodium discharge the salt either as crystals on the surface or 

 as amorphous deposits in the sporangium wall and stalk. In some 

 genera the granules are also collected in vesicles connected with a 

 system of threads which branch in all directions within the 

 sporangium from the base to the walls. When the lime has thus 

 been got rid of, and the system of the threads or capillitium has 

 been formed, nothing remains but the pure spore-plasma with its 

 host of nuclei, for as the plasmodium has grown the nuclei have 

 multiplied pari passu. Each nucleus now gathers round itself just 

 sufficient protoplasmic matter to form a spore of the exact size 

 peculiar to each species ; these take a globular shape and clothe 

 themselves with a coloured wall often beautifully sculptured, or 

 rough with spines, and the whole of the plasma is thus converted 

 into spores. The time required for the full development of the 

 spores from the first production of the sporangia varies from about 

 12 hours to three or four days according to the species. The 

 capillitium is largely developed in some genera and is absent in 

 others, but when present it is always formed before the spores, and. 

 is in no way connected with them. 



The drawings exhibited to the Club represented species selected 

 to illustrate some of the more striking genera. Among these I 

 may refer to the following, which are very commonly met with 

 viz., Trichia, Arcyria, Stemonitis, PJiysarum, Craterium, and 

 Dictydium. 



FIG. 1 : Tricliia varia. A very abundant species inhabiting old 

 decayed stumps. 



In the Genus Trichia the capillitium is composed of free hollow 

 threads, which lie among the spores. These threads, or elaters, are 

 provided with thickened spiral bands, two to five in number, 

 which wind along their entire length, giving a rope-like appearance 

 to the thread. They are very sensitive to moisture, and when 

 breathed upon the unequal thickness causes them to writhe and 



