Harper. — C ell- Division in Sporangia and Asci. 515 
a result of metabolic changes beginning at the nucleus, the 
spore-plasma becomes chemically altered and different from 
the adjoining epiplasm as soon as it is cut off by the fused 
rays, we might imagine that the interaction of the thus 
differentiated spore-plasma and epiplasm could be maintained 
and a bounding layer produced, as it is supposed to be formed 
by the action of water on the surface of the Amoeba. That 
such differences could be so soon produced, and that the 
epiplasm could produce on the spore-plasma the same effect 
which so foreign a substance as water produces on the surface 
of an Amoeba , seems difficult to imagine. Biitschli’s theory of 
a permanently differentiated outer layer (oily in its nature) 
fits much better with the phenomena here. The indepen- 
dence of motion of the rays through the ascus-plasma, com- 
parable, as I have already pointed out, only to the vibratile 
activity of cilia, also seems to demand the assumption of 
a very considerable difference between their composition and 
that of the medium in which they move. In later stages the 
spores enlarge somewhat, and come to lie in a single row in 
the axis of the ascus. In Fig. 48, owing to a sharp bend in 
the upper end of the ascus, the spore-row seems to come 
nearer the apex of the ascus than is really the case. Spore- 
walls are still lacking at this stage. The spores are less 
flattened on each other, and are beginning to take on the 
elliptical outline of the fully ripened condition. Central 
bodies, such as are quite conspicuous on the spore-nuclei of 
Erysiphe at this stage, are hardly ever to be discovered in 
Lachnea. 
In the above description I have not attempted to redescribe 
all the points in the process of spore-formation which are 
identical with those already described for Erysiphe. I have 
rather aimed merely at presenting those minor points in 
which the process varies in Lachnea from the condition in the 
other forms described. 
The main point of difference between Lachnea and Peziza 
Stevensoniana and Ascobolus furfuraceus in this process is 
that in Lachnea the anaphases in the last division forming the 
M m 
