Dublin Microscopical Club. 127 
calling to mind the involucrum, with its projecting leaflets, of cer- 
tain Composites, say such as that of Centaurea nigra. This occurs 
isolated, single examples turning up now and again. The question 
is, what can it be? It has never shown any sign of life or change 
of condition. 
A Form of Aspergillus. —Mx. Greenwood Pim showed a peculiar 
black form of Aspergillus from the interior of a fig, which it had 
completely metamorphosed, It was considerably smaller in all its 
parts than Aspergillus glaucus ; and its intense brownish-black colour 
would seem to point to its being at least a distinct variety. 
December 15, 1882. 
Spores of Tuber estivum.—Mr. Pim showed sections of the (so- 
called) common Truffle (Tuber estivum), from Farmleigh Gardens, 
Castieknock, co. Dublin, where it grows in considerable abundance 
and is used for culinary purposes. The peculiar alveolate spores 
distinguishing it from 7. brunale, the other species used as an escu- 
lent, were well marked. 
Structure of Stem of Urvillea.—Dr. M‘Nab exhibited sections of 
the stem of Urvillea ferruginea, a Brazilian plant belonging to the 
natural family Sapindacee. The stem was triangular, with a row 
of hairs at each angle. The stem contained a ring of united fibro- 
vascular bundles in the centre with a pith, the bast showing the 
bast-vessels with great clearness, while the bast-fibres were wanting. 
Three double bundles were developed, one at each angle of the stem ; 
and a ring of sclerenchyma surrounded the stem a short distance 
below the epidermis. Collenchyma existed in six patches, one at 
each angle and one in the middle of each face. 
Nerve-endings ta Frog’s Muscle.—Dr. Knott showed preparations 
presenting examples of nerve-endings in muscle of frog. 
Zygospore of Cosmarium cucurbita (most probably) shown.—Mr. 
Archer exhibited what appeared to be the zygospore of the common 
Cosmarium cucurbita, rotund and smooth, the parent semi-cells 
attached by their oscula to the spore; he spoke of this appearing to 
be the zygospore of the species mentioned, as one could not feel 
absolutely certain that it was truly so, a number of unconjugated 
examples occurring in the gathering; but if not so, it would be 
difficult to suppose to what other species the example could apper- 
tain. The doubt arose from the semi-cells appearing to be slightly 
distorted, that is somewhat dilated at the ends, thus losing the 
character of outline appertaining to this inornate and very common 
species ; but frequent as it is, it does not appear to have hitherto 
shown its zygospore. 
Section of Olivine Dolerite.—Prof. Hull exhibited a thin section 
of olivine dolerite from Scalot Hill, near Larne, co. Antrim. 
