a parasitic Fungus on Sugar-Cane and Cacao. 685 
Demerara. Experiments, which are described below, were 
undertaken to follow the development of this cacao Fungus, 
starting from a single spore. The behaviour of the two forms 
was therefore studied side by side, and the results are given 
in the following. 
In February and March of the present year I was requested 
by Dr. Morris, the Imperial Commissioner of Agriculture for 
the West Indies to visit Grenada and to report on the nature 
and extent of the. damage done to cacao trees by fungoid 
diseases. While engaged on this mission I found that in 
addition to its occurrence on cacao trees, the Fungus was 
common on growing cacao pods, where it was apparently 
the cause of a rather serious disease. Infection-experiments 
with pure cultivations of the Fungi found on canes and on 
the cacao tree, on their respective host-plants, and also cross- 
infection experiments were carried out during this time, and 
are described below. Later in the present year a Fungus 
on cacao was noted in St. Lucia, St. Vincent, and Dominica, 
which proved to be identical with that found in Grenada. 
The Sugar-Cane Fungus. 
The external appearance of a sugar-cane in which this 
Fungus occurs is not unlike that of a cane attacked by the 
Melanconium stage of Trichosphaeria Sacchari. The rind is 
ruptured by the growth of dark bodies underneath, which are 
arranged in more or less vertical lines (PI. XXXVII, Fig. 1). 
Transverse sections through these black areas show that the 
disturbance is caused by the development of colonies of true 
pycnidia formed just beneath the rind, and which are in 
connexion with a dark-brown septate-branched mycelium 
abundant in the tissues of the cane (Fig. 2). The wall of the 
pycnidium is seen to be made up of two distinct layers, an 
outer peridium made up of dark-coloured, thick- walled hyphae 
forming a definite tissue, and an inner hymenium of thin- 
walled colourless cells, charged with granular contents, which 
are no doubt destined for spore-formation. In the cavity of 
the pycnidium short conidiophores, 20-40 /x in length, bearing 
