43* 



SECOND PART. MYCETOZOA. 



The conformation of the sporangia in Stemonitis runs differently in one respect 

 from that of all other known forms. The slender threads of the plasmodium, which 

 lives in rotten wood, unite at first into large cylindrical or ellipsoid bodies of 

 homogeneous protoplasm, which rest their broad surface on the substratum. Then 

 a hollow cylindrical firm central column is separated off in the protoplasmic 

 body, and rises vertically from a membranous base resting on the substratum, 

 advancing by acropetal growth (Fig. 186 a, b\ The mass of protoplasm, the 

 longitudinal axis of which is traversed by the column, stretches at first at the same 

 time in the same direction ; but it afterwards loses hold of the substratum at its base 

 and clinging to the central column moves on it a certain distance upwards till at 



FlG. 186. Sremanitfs ftrruginea. a a com- 

 mencing sporangium with the first beginning of the 

 central column. * sporangium which has reached 

 its mature form.capillitium and spores not yet formed. 

 Both figures represent specimens in optical longitu- 

 dinal section hardened in alcohol and then rendered 

 transparent in glycerine, oniagn.iztiuies, b 15 times. 



FlG. 187. Cerathim hydnoides. Forming of 

 sporophores on plasmodia which have come to the 

 surface of a piece of wood. Successive stages of 

 development according to the letters a c ; c the 

 mature state. After FaminUin and Woronin, about 

 3 times the natural size. 



length it becomes stationary and developes into a sporangium in the usual manner 

 (Fig. 1 86 b}. The sporangium is supported on the lower portion of the central 

 column which is laid bare by the upward movement of the protoplasm, as on a stalk. 

 Other genera allied to Slemonitis behave in a similar manner. Further details must 

 be sought in the different monographs. 



The plasmodia of the ectosporous Ceratium hydnoides come forth to the 

 surface from the interior of the rotten wood which is their habitation to form their 

 spores (Fig. 187). Here they appear at first to the naked eye as white cushion-shaped 

 bodies (Fig. 187 a); examination with the microscope shows that these cushions are 

 formed of countless microscopically slender plasmodium-branches, united together in 

 every direction into a net-work of narrow meshes, such as is shown in Fig. 188 a. The 

 meshes are filled with a hyaline homogeneous gelatinous substance of watery 

 consistence, which forms a thin coating on the surface of the net-work. To form 

 the sporangia cylindrical often dichotomous outgrowths, resembling the spikes of a 

 Hydnum and growing to be a few millimetres in length, rise erect from the surface 

 of the cushion (Fig. 187 b, c). The whole body of protoplasm moves into these 

 outgrowths, leaving only a* thin flat layer to connect it with the substratum. During 



