272 D. D. CUNNINGHAM. 
recorded that while at dawn the cultivation showed no traces of 
the presence of sporangia, an abundant crop of such bodies 
appeared within the course of the next few hours. This is merely 
an illustration of the fact that the development is regularly 
limited to the period between dawn and noon or at latest 1 p.m. 
If sporangia have not appeared by the latter hour they will not 
appear until the following morning. At first sight it appeared 
not improbable that light-conditions were the determinent of this 
phenomencn, but experiments proved that this was not so, for 
the development followed the same course even where all light 
was carefully and absolutely excluded. 
The sporangia and spores described above are such as occur 
by far most regularly and may be regarded as the typical form 
of reproductive bodies in the organism, but certain other spo- 
rangial bodies occasionally accompany or replace them, which 
although differing in various particulars are, I believe, mere 
aberrant varieties determined by the coincidence of special con- 
ditions. In the first place, in place of those containing normal 
spores, only varying within the limits as to size and form 
ordinarily encountered, we also meet with sporangia which, in 
addition to normal spores, contain a greater or less proportion 
of irregular, unformed looking bodies (Fig. 20). 
Fic. 20.—Abnormal forms of spores X 1000. 
These, as a rule, are of larger size than the others, but are 
_ connected with them by a series of intermediate forms, and 
exhibit a precisely similar series of developmental changes in 
passing into a state of activity. Sporangia in which such bodies 
abound are frequently of an irregular form, and in some cases 
may assume a dendritic character, appearing in branched tufts 
which may attain a height of 1:5 mm. and a breadth of 2 mm. 
(Pl. XVIII, figs. 4, 5); in other cases either in association with 
these ill-formed spores or in normal sporangia, isolated encysted 
Amoebe may be present, or bodies which resemble the frame- 
work of an Ameeba containing sporoid bodies, 
