258 PROCEEDINGS OF SOCIETIES. 
Protococcus pluvialis in large numbers in a pond near 
Harleston, Norfolk, and exhibited specimens. 
A paper by Fitzmaurice Okeden, Esq., “On the Diato- 
mace of the South of Wales,” was read, illustrated by 214 
mounted specimens of Diatomaceze, which were presented to 
the Society. The special thanks of the Society were returned 
to Mr. Okeden for his valuable present. 
The meetings of the Society were then adjourned until 
October next. : 
Some difficulties having occurred in the practical applica- 
tion of Whitworth’s gauges recently recommended by the 
Society for the purpose of establishing an uniform screw for 
object-glasses, it was resolved, at the meeting of the Society on 
May 19, that ‘“'Two dozen steel taps be made for the use of 
makers of microscopes, wishing to adopt the universal attach- 
ment for object-glasses recommended by the Society.” 
If one of these taps be made to. enter the body of the 
microscope, it will receive any object-glass having a screw of 
the dimensions recommended, and the cylindrical gauges will 
not be required. 
The set of taps is in course of construction, and may in a 
few days be obtained of Mr. Williams, the Assistant-Se- 
cretary to the Astronomical Society, Somerset House, at the 
price of 5s. each. 
Dusiin Naturat History Socrety, May 7th, 1858. 
The President in the chair. 
The Rev. Eugene O’Meara read the following paper, “ On 
the occurrence of Anthozoids in Pleurosigma Spencerii.” 
“On Friday evening, April 30th, I was engaged in the 
examination of a gathering I had made two days previous 
from a running stream. On looking into the microscope I 
was much struck with the peculiar appearance of one of the 
forms that first presented itself in the field, a Plewrosigma 
Spencerii. The usual colour of the endochrome in this 
species is pale brown, but in the present instance it was a 
beautiful green. A number of granules of a bluish-green 
colour were distributed through the cell. In a few minutes 
I observed that the greater portion of the granules, at least 
