On two species of Heterosporhim. particularly Heterosponum echinulatum 
7 
and in others branches of radiating hyphae. After about a week’s growth the origin of the 
conidiophores and coloured vertical hyphae could no longer be made out, owing to the 
very compact growth of the mycelium. Finally the sunken mycelium changed from 
brown to a red brown in colour, thus distinguishing the mycelia on glucose agar from 
those formed upon the other media. The colonies were small and became dome-shaped, 
and appeared grey in colour when viewed from above, i. e. from the bottom of the slide 
containing the hanging-drop. From the opposite side they appeared grey with a decided 
central orange patch, due to the very numerous coloured vertical hyphae which were not 
formed at the edges of the mycelia, but only from the middle portions. The conidio¬ 
phores which were invisible to the unaided eye consisted of one to two, and sometimes 
three prolongations of the first head. 
2. On Maltose agar. 
The growth was more abundant than upon glucose both in quantity of spores 
and the richness of the mycelium which was bright green in colour. Short vertical 
pigmented hyphae were formed, but were few in number and could not be well seen. 
The conidiophores were visible from below as bright specks. 
3. On Meat extract agar. 
The vertical hyphae were very numerous; but were not so deeply coloured as 
those in glucose or salep agar of the same age; the cytoplasm of the mycelial cells 
was granular in appearance. Conidiophores began to be produced upon the third day 
and were short and very numerous. At the end of a fortnight the mycelium was 
scanty as compared with that on glucose or maltose. Very numerous, long, brown 
coloured, vertical hyphae were present which were easily seen owing to the thinness 
of the mycelium; whereas in glucose the reverse was the case. The conidiophores 
were visible to the unaided eye, many with three prolongations from the first head; 
the spore chains contained generally three spores each. 
4. On Plum-juice agar. 
After germination the growth was not so rapid or extensive as in glucose or in 
salep agar. The mycelial cells contained numerous oil-drops, as indeed was the case 
on the preceding media; but on plum-juice agar they were very much more noticeable. 
Later, the colonies increased in size and became larger than those upon other media 
of the same date of inoculation. The radiating hyphae of the mycelium were not 
wavy but bent at sharply marked angles and branched. The conidiophores, few in 
number and placed at the edge of the colony were long and finally produced not more 
than two prolongations. The sunken mycelium at first green in colour finally became 
olive green. 
5. On Salep agar. 
The whole growth consisting of both sunken and aerial mycelia was scanty; 
the surface mycelium was greyish in colour and contained oil-drops in its individual 
cells. Very numerous conidiophores and conspicuous short, brown coloured, vertical 
hyphae were formed. The conidiophores at first colourless became brown-grey and 
resembled the vertical hyphae in appearance, but were much thinner than these; they 
formed from two tQ four prolongations from the first formed head. The growth upon 
this medium was fairly rapid. 
Heterosporium echinulatum. 
1. On Salep agar. 
The colonies produced spores on the third day after inoculation. The conidio¬ 
phores took the form of branches given off from the main germ hyphae which had 
greatly increased in size and formed the main hyphae of the mycelium (fig. 26 b). 
After five days the growth was still scanty and straggling. Very little white aerial 
mycelium was present; but the young conidiophores were numerous. It was observed 
that the conidiophores alw T ays produced prolongations from the first formed heads 
(figs. 28, 29). Later on the conidiophores become light-red brown in colour and the 
scanty sunken mycelium grey-green, the latter consisted of short barrel-shaped cells. 
The main hyphae of the mycelium, which were considerably branched, were formed 
from the original germ tubes and remained the largest hyphae of the whole growth. 
They were always recognizable, as no other thick hyphae were produced, and remained 
