PHYSARELLA MIRABILIS PECK AND STEMONITIS FUSCA ROTH 28 1 
as found in PhyvSarella. Figure 17 shows an early stage in which the 
tubular space in the still foamy protoplasm is bounded only by a thin 
membrane, no wall deposit being as yet apparent. I have not at- 
tempted to show in great detail the various degrees of thickening of 
these developing threads, instances of which are rather common in the 
preparations. Figures 18, 19 and 20 show this phenomenon inciden- 
tally, and perhaps as convincingly as a more detailed series of drawings 
would. 
Figure 18 represents the attachment of a capillitial thread to the 
columella. The thread has here attained some thickness, as may be 
observed further away from the central columella where the thread 
widens somewhat. At this wider portion the wall appears somewhat 
wrinkled or irregular. Near the columella the thread is of sufficient 
degree of attenuation to obscure the lumen. The protoplasm in this 
instance is in close contact with the thread. The expanded attach- 
ment of the capillitial thread to the columella is of some interest, since 
it is evident that the broader attachment is a continuation of the outer 
portion of the thickened central columella. So far as my own observa- 
tions have gone, I have not found the lumen of the columella to be 
continuous with the lumen of the capillitial thread, which point is in 
agreement with De Bary's findings. 
Figure 19 shows a cross section of material in a similar condition; 
here, however, the protoplasm has been shrunken away from the thread 
and half the columella, possibly by the initiation of cleavage. Within 
the columella may be noted the presence of some stainable substance, 
probably protoplasm. 
Figure 20 represents a case in which cleavage is just beginning from 
the surface of the sporangium. The nuclei are in the equatorial 
plate stage, and the protoplasm is distinctly more finely granular and 
richly stainable at the periphery, perhaps due, as Harper suggests, to 
contraction of sporeplasm and extrusion of water. As is shown in the 
figure, the reticulations that form the net-like capillitial sac of the 
mature sporangium have been already formed just within the outer- 
most portions of the protoplasm. Deeper down within the more 
foamy protoplasm the threads are still, in some cases, clearly in contact 
with the cytoplasm. In most cases in this preparation it was clearly 
evident that the threads are of a hollow nature. Although any rela- 
tion to cleavage is not definitely shown in this figure, it is apparent 
from a study of the sections that here also the cleavage furrows are 
