514 
PROFESSOR W. C. WILLIAMSON ON THE ORGANIZATION 
On applying Kleiss’ oil-immersion lens to the specimen illustrated by fig. 44, new 
phenomena were brought to light. I had already obtained some faint glimpses of two 
or three delicate threads springing from some of the pointed murications of the spines 
in such specimens as fig. 41, and which threads appeared to lose themselves in the 
investing plastic substance. In the specimen now under consideration we find that 
such threads are but the commencements of a very complicated system which permeates 
the plastic substance in every direction. I was long inclined to believe that these 
branching threads anastomosed to form a regular network. I noticed that whenever 
two of them met there was a small but very decided apparent thickening of the tissue, 
visible even when the threads themselves were almost invisible ; but later observations 
each have led me to conclude that such is not the case, but that they merely start from 
each pointed mucro as at fig. 44, a, a, a , and spread through the plastic substance by a 
succession of dichotomous divisions. It is scarcely necessary to say that the structures, 
a, a, a, of fig. 44, represent the free portions of spines that have been intersected as 
they pass through the plastic element a little above the outer surface of the capsule- 
wall, but similar threads are given off from the upper surfaces of the branching 
tubes, a', a'. 
I have already pointed out that in the more matured spines, as in fig. 47, a', we 
find the mucronate projections of specimens like fig. 44 also converted into branching 
tubes. This condition is well represented by fig. 50, where three of the spines are seen 
intersected transversely, whilst a fragment of a fourth appears in its longitudinal 
aspect. All four spines demonstrate that the mucronate projections, with then divergent 
threads of fig. 44, are here replaced by freely branching tubes which radiate in every 
direction. I have examined the section from which this figure is taken to see if I 
could discover any anastomoses between the separate sets of branching tubules; but 
I have failed to do so. In all the cases where such anastomoses appeared to exist, it 
became manifest that separate branches merely overlaid one another. 
I think there can be no doubt that the branching threads of fig. 44 are identical with 
the branching tubules, h, h, of fig. 50. If so we must assume that the former is their 
undeveloped condition, whilst in the latter they have not only attained, but have even 
passed them maturity. Fig 50 represents them in the most perfect form in which I 
have yet found them; but it is obvious that the branches, h, h, of that figure are but 
the truncated bases of what were at one period much more extended ramifications. 
Wherever we see into these truncated branches, we find open mouths of thin-walled 
cylinders, as at h', h'. 
It appears to me most probable that the external capsule-wall indicated in all the 
specimens figured by the letter a, is a cellulose exosporal membrane, which has been 
prolonged into numerous radiating branching tubes, the secondary branches of which 
very closely resemble those figured by Van Tieghem and Le Monnier in their 
‘ Reclierches sur les Mucorinees but having their ramifications more multiplied and 
* ‘ Annales des Sciences Natnrelles,’ 5 e serie, Bot., tom. 17, plate 20, figs. 12 and 13. 
