A New Species of Sigmoideomyces Thaxter. 245 
posed of a radiating mass of tapering, branched and apparently 
dichotomising hyphae, from which arise laterally the globose 
conidiophores on slender pedicels. The conidiophores are borne 
only on the stouter branches, towards the centre of the mass, 
so that they are protected by the sterile, apical portions of the 
hyphae. They arise in pairs, one on each side of the large cells 
which form the angles of the dichotomies. 
The branching of the upper portions of the hyphae is strictly 
monopodial and in spite of appearances I am persuaded that it 
is so throughout and that the apparent dichotomy of the basal 
portions is due to secondary divergence of branches which are 
not in reality of equivalent rank. Reference to Pl. XII, fig. 5 
will make this point clearer. Each conidiophore bears 25-30 
short, conical sterigmata on each of which is one spherical, 
minutely echinulate conidium. The development of the conidium 
follows that of the conidiophore in point of time, being budded 
off when the latter has practically reached its full size. Both 
conidia and conidiophores are very caducous and the latter 
also readily collapsible, except perhaps when fully mature. The 
angle-cells, likewise, on which they are borne seem easily dis- 
torted by the leverage of the branches. 
One curious feature, in which this species is peculiar, is the 
development of little prominences on the cells towards the apex 
of the filaments, easily seen with a low power and suggesting 
sterigmata, though no propagative bodies have ever been seen 
attached to them. High magnification on the other hand, 
reveals that each hypha bears a dense epiphytic flora of fila- 
mentous bacteria (Leptothrix?) which look exactly like flagellar 
appendages, particularly as one or more is regularly attached 
to each of the aforementioned prominences. 
The vegetative mycelium, from which these perithecial-like 
balls of hyphae arise, is scanty and consists of long, unseptate 
filaments with an average diameter of 2-3 and very sparingly 
branched. 
The claim of this new form to specific distinction rests on 
the following points:—(a) The rectilinear fertile hyphae, lacking 
that sigmoid curvature whence the genus takes its name. This 
is an important departure from the type, although in a character 
probably subject to environmental modification, but the ensemble 
of habit and structure undoubtedly points to its inclusion in 
the genus even though it should thus render the generic name 
no longer apt. That is not a matter on which too much stress 
need be laid for the validity of this or indeed of most genera 
does not rest on a single feature but properly on the syndrome 
of characters in the generic definition. (b) The rigidly divaricate 
and pseudo-dichotomous branching of the fertile hyphae. 
(c) The prominences on the apical portions of these hyphae. 
