2gi 
and oilier Mycetozoa. 
Immediately after it has taken the sporangium-form. On one 
occasion this change was closely watched in the case of a sub- 
merged sporangium ; the chalk granules were at first dis- 
tributed over the surface, but in a short time they slipped, off 
and were deposited in a little heap at the side. 
On another occasion, when possibly some movement had 
produced a rupture in the soft wall of an immersed sporangium, 
a portion of the spore-plasma protruded through the rent, and 
was observed to branch into lobes and to divide into spores in 
the same manner as was noticed in the spore-formation of 
Brefeldia maxima , described in Annals of Botany, Vol. II. 
p. 18 ; each young spore, on constricting itself off, contained 
for a time a fluctuating vacuole, as was observed in the case 
of Brefeldia. 
The species most closely allied to Chondrioderma dijforme 
appears to be Didymium dubium , which differs chiefly in the 
character of the outer wall and in having smaller and paler 
spores and a more profuse capillitium. The plan of the 
sporangium is precisely the same, and it has the same isolated 
habit ; it is only recorded in Saccardo’s Sylloge Fungorum 
as occurring in Bohemia, but is fairly abundant among dead 
leaves in one locality near Lyme Regis. It is interesting 
in connection with the subject of this paper in being liable 
to much variation. 
The typical spores are nearly or quite smooth, of a pale 
violet-brown colour, and measure 7-9 /1, but specimens are not 
infrequent with large spores nearly uniform in size, the ex- 
tremes ranging from 12-15 /x, and distinctly echinulate. The 
capillitium is dense, dark, and rigid, anastomosing at the 
extremities, but it is sometimes delicate and flexuose, though 
always coloured. The outer crust is a loose aggregation of 
large and very beautiful stellate crystals, but now and then 
we find it closely compacted, with but slightly crystalline 
character, and nearly resembling that of Chondrioderma 
dijforme . I have not succeeded in obtaining the plasmodium 
of Didymium dubium from a cultivation of the spores in a 
hanging drop or with cress-seeds on blotting-paper, although 
