Differentiation 



227 



Polysphon dylium 

 violaceum 



P. pallidum 



D. purpureum 

 Dictyostelium 

 mucoroides 



Fig. 8-26. Sorocarps of various members of the Acrasiaceae. (From K. B. Raper.) 



selves out and form sorocarps typical of each species. The specific char- 

 acter of the sorocarp can be shown to be carried by its spores. 



Sussman ( 1955 ) has found a number of mutants of Dictyostelium dis- 

 coideum in which the aggregating groups, and consequently the size of 

 the sorocarps they form, is much smaller than normal. In some of these 

 the fruiting body consists of as few as 12 cells but it still retains the form, 



