I9I3. 
Irish Societies, 6i 
DUBLIN MICROSCOPICAL CLUB. 
January 8. — The Club met at l.einster House, IJ. McArdle, (Vice- 
President in the Chair) 
N. CoLGAN exhibited the radula or hngual ribbon taken from one of 
two specimens of Dovis proxinia. Alder and Hancock, which had been 
dredged at Malahide, Co. Dublin, by Professor Bayley Butler on the 
loth December last. This species is superficially so similar to D. aspera 
of the same authors, that it is hardly po.ssible to distinguish them without 
comparison of the radulae. But an examination of this organ shows a 
radical difterence of structure which at once separates the two species 
and has induced J^ergh to adopt D. proxinia as the type of a new genus, 
Adalaria, intermediate between the genera Acanthodoris and LameUidoris. 
While the lingual formula of Adalaria proxinia is lo-I. i. I-io. in 1). 
aspera it is 2 -I. i. I-2. There appears to be no previous record of A. 
proxinia for Irish waters, so that Professor Bayley Butler may be con- 
gratulated on the addition to our marine fauna of a new species of nudi- 
branch. It is not improbable that the species will before long be discovered 
in other Irish stations. 
Prof. G. H. Carpenter showed specimens of a blind springtail — 
apparently a new species of Cyphoderus — recently collected by Dr. Nelson 
Annandale (superintendent of the Indian Museum, Calcutta), on the 
borders of the Lake of Galilee, close to the town of Tiberias. The insect 
which will probably be described and figured in the Journal of the Royal 
Asiatic Society of Bengal, is nearly related to species of Cyphoderus from 
the valley of the Nile. A corresponding affinity between the fishes of the 
Jordan and Nile valleys has long been known. 
W. F. GuNN showed the adult form of Corethra plumiconiis, a dipterous 
fiv, well known for the beautiful plumose antennae which it possesses, 
and which in the larval form is known as the " phanton^. " or " glass " 
larva. This object was chosen for exhibition principally to demonstrate 
a method of illumination which seems advantageous when a low power is 
used on certain objects which provide sufficient contrast. Underneath 
the stage and resting upon the substage of the microscope a piece of 
roughly ground pure white opal glass is placed, and a strong beam of 
light is focused on it by means of a bull's-eye condenser, or other suitable 
optical arrangement. This gives a pure white background on which the 
object stands out with great clearness. As the rays of hght are broken 
up and diffused by the rough surface of the glass, there is an entire absence 
of reflection from one part of the object to another which results in a 
corresponding distinctness and sharpness of the image. 
Professor Carpenter remarked that a somewhat similar result is obtained 
in many dissecting microscopes by the use of an opaque white paper disc 
in place of the usual reflecting mirror. 
D. McArdle showed dissected capsules of Tetraphis pellitcida from 
specimens recently collected in the Co. Wicklow, disclosing the spores 
and showing the possible origin of the peristome, composed of four solid 
conical teeth, derived from the fission of the whole cellular tissue of the 
