Olive—Cytological Studies on Ceratiomyxa. 769 
fragment. As was mentioned above, the protoplasm in such 
instances has apparently become massed in places on the sur¬ 
face of the sporophore, instead of becoming drawn out into 
narrow strands as seems usually to be the case. Finally, the 
uninucleated segments themselves continue the outward move¬ 
ment, with probably little if any interruption, as single, inde¬ 
pendent, amoeboid cells until each forms finally a stalked rest¬ 
ing spore. 
Ho advance has been made in this study in the problem as 
to what forces initiate and direct the process of cleavage in 
Ceratiomyxa. I can therefore add nothing definite to the view 
that cleavage results probably from tensions produced by con¬ 
tractions due to loss of water (Harper, ? Q0) ; or to the idea 
that the phenomenon comes from local contractions in the cy¬ 
toplasm (Swingle, ? 03). 
A comparison of various low organisms with respect to their 
use of mucus, or slime, in building up their fructifications is of 
some interest. Those four groups of organisms—the Myxomy- 
cetes, Acrasieae, Labyrinthuleae and Myxobacteriaceae—- 
which unite in colonies to form their fungusdike fructifica¬ 
tions, excrete in some cases large quantities of slime, which 
may be utilized in various wmys to assist in raising the fruit- 
body above the substratum. 
It will be remembered that in the fructification of Ceratio¬ 
myxa, the entire supporting structures of the sporophore—the 
base, the main axis and the numberless stalks borne on the sur¬ 
face—are ‘wholly composed of a gelatinous, slimy sub¬ 
stance. Ho protoplasm is left in these regions, since all 
of the living material migrates to the tips of the slender 
stalks. Some of this slimy substance may be seen in the 
lacunae and furrow's of the young fructifying reticulum 
(Fig. 1). As the plasmodium creeps upward, slime is grad¬ 
ually added to the mass left behind on the substratum 
(Figs. 2, 3, 10). The slimy matrix in which the creeping 
reticulum is enclosed, and the slimy central axis, w T hich is 
finally entirely deserted by the protoplasm, thus serve as 
a semi-solid substratum on which the climbing movements 
take place. Even the amoeboid cells formed finally by 
