Olive—Cytological Studies on Ceratiomyxa. 7 65 
up of a relatively dense, contracted reticulum, in which the 
strands are thick and the interprotoplasmic spaces minute 
(Harper, ’00, p. 221). In the development of this form into a 
mature fructification, the protoplasmic reticulum continues to 
contract so that the superficial strands are withdrawn toward 
the center. In Ceratiomyxa we have a similar heaping up of 
the plasmodium which has crept to the surface, thus forming 
a tiny cake or cushion of whitish protoplasm. This mass is 
seen to be made up, as in Fuligo at a similar stage, of a 
dense reticulum. Obviously in both cases the plasmodium in 
this condition results from an aggregation, or condensation, 
of the vegetative reticulum. Sections of this early stage ~n 
Ceratiomyxa (Fig. 1) show irregular lacunae filled with 
slime, and deep surface furrows which separate the thick 
strands. Such sections, as will he readily noticed, hear a super¬ 
ficial resemblance to the illustrations of cleavage in the sporan¬ 
gia of Pilobolus (Harper, ’99, Figs. 14-15), Fuligo (Har 
per, ’00, Fig. 1) and Phycomyces (Swingle, ’03, Fig. 21). 
But the surface furrows of the actively creeping plasmodium 
of Ceratiomyxa are certainly very different in origin and func¬ 
tion from the cleavage furrows which cut into the quiescent 
masses of spore-plasm of sporangia. 
Following the heaping up of the plasmodium on the surface 
of the substratum comes the further creeping out from each 
mass of one to several cylindrical sporophores. As shown ’n 
sections (Figs. 2-3), and even more clearly in Famintzin 
and Woronin’s Plate I, Figures 4-8, the reticulum at this 
stage, although forming a much finer meshwork, has been 
greatly expanded as compared with the appearance in the ses¬ 
sile, compact mass on the surface. The spinning out of the 
protoplasmic meshwork into finer and finer strands and the 
consequent increase of the reticulation results obviously from 
the continued creeping out of the plasmodium to form the pe¬ 
ripheral network, which finally spreads in a thin layer over the 
surface of the cylindrical sporophore. The strands in many 
instances ultimately become so attenuated as to he only one 
nucleus thick. It is clear that such an attenuation of 
the strands composing the fibrous network must he ae- 
