BRITISH MYCETOZOA. 



I I 



the capillitium (referred to afterwards) extending from the columella 



to the circumference. The 



nuclei in the plasma still 



present the same appearance 



as those observed in the 



streaming Plasmodium. In 



about another hour the nu- 

 clei show the beginning of 



karyokinetic division (Fig. 6); 



as the process advances the 



plasma becomes separated 



in masses of two spores' 



capacity (Fig. 7) ; an hour 



later, and karyokinesis is 



completed, the nuclei have 



divided, and the youngspores 



are forming. As the dark 



spore - walls are produced 



the colour of the sporangia 



rapidly changes, and in about 



twenty hours after the first 



concentration of the Plas- 

 modium they have matured 



and present the appearance 



of a cluster of minute black 



pins, with round or oblong heads, standing in regular order on the 



wood. The sporangia of different species take various forms, such 



as are represented by the woodcuts illustrating the different genera, 



with numerous modifica- 

 tions. They may be either 

 symmetrical or irregular in 

 shape, and with or without 

 a stalk ; when sessile and of 

 irregular form, as shown in 

 Fig. 13, they have received 

 the name of plasmodiocarps. piasmodiocarp. 



When many sporangia .ffithalium. 

 are combined, and their 

 separating forms are imper- 

 fectly developed, the cluster 

 is called an cethalium. 



When the sporangia are Hypothallus. 

 formed, a membranous or 

 calcareous residuum or hy- 

 pothallus is often left by 

 the Plasmodium, forming a 



base on which the sporangia are seated. 



In most genera a capillitium, consisting of a system of threads, Capillitium. 



MATRICHA OBTUSATA PreilSS. 



From a stained preparation of a young sporangium, 

 showing the Plasmodium separated into 

 rounded masses about groups of nuclei, which 

 are dividing by karyokinesis ; the nuclear 

 division has reached the "spindle stage"; 

 the spindles are seen in profile in all cases 

 but one, in which the equatorial plate is seen 

 from one of the poles of the spindle. Magni- 

 fied 1200 times. 



Fig. 7.— COMATRICHA OBTUSATA PreuSS. 



From a stained preparation of a young sporan- 

 gium, showing: the Plasmodium separated 

 into masses of two spores' capacity round 

 the nuclei, which have almost divided by 

 karyokinesis. Magnified 1200 times. 



