Some Questions which they Suggest. 



59 





clothe themselves with a cellu- 

 lar membrane, heap themselves 

 together at the summit of the 

 structure, and thus form a 

 chaplet of spores. 



In Dictyostelium mucoroides a 

 very similar course of growth has 

 been observed. The mass which 

 collects at the central point 

 differentiates itself into a 

 column, a membraneous veil to 

 the column, and a residual mass 

 surrounding the column. As 

 the column grows upward this 

 residual mass does the same, 

 and thus withdrawing its lower 

 part from the ground it wanders 

 up the stalk and forms a cap or 

 crown which turns into spores 

 without a trace of capillitium. 

 Fig. 19 shows in section the 

 nearly adult form of this or- 

 ganism. 



A still more singular history 

 is presented by a third species, 



the Poli/spliondulium violaceum. c > "Remains of Membrane 



broken by growth of the 

 Here the early stages corre- Sporangium. (After ,J3re- 



spond with those already de- feld>) 



scribed, the plasmodium, or more accurately the pseudo- 



19. Dictyostelium 



