116 ARCHER, ON STEPHANOSPHHRA PLUVIALIS. 
Suriray.—Notices sur quelques parasites et produits organ- 
iques du Lombric terrestre ; in ‘ Ann. Sciences natur.,’ 
2 sér., “ Zool.,” tom. vi, 1836, pp. 853—358. 
Treviranus, G. B.—Ueber die Zengung des Erdregenwurms ; 
in ‘ Tiedemann u. Treviranus’ Zeitschr. f. Physiol., Band. 
Heft 2, 1835, pp. 154—166. 
Wicumann, Joh. Ern.—Vom Giirtel des Regenwurms ; in 
‘ Berlin. Beschaftgen, Bd. ui, 1777, pp. 281—240. 
Recorp of the occurrence, new to Irevanp, with Nor, of a 
Peculiar Condition of the Votvocinaceous ALGA, STEPHA- 
NOSPHHRA PLUVIALIS (Cohn), and Observations thereon. 
By Witi1am Arcuer.* 
Tue discovery in Ireland of the very interesting and very 
beautiful and apparently very rare organism, Stephanosphera 
pluvialis (Cohn), would in itself alone be worthy of a record 
in the ‘Proceedings’ of this society. But masmuch as, 
whilst I had a supply of this ‘ Volvocine” in my possession, 
a remarkable phase or condition in its history—so far as I am 
aware, not before observed in this form, though not without 
parallels elsewhere—presented itself to my notice, the value 
of that record becomes thereby in so far enhanced. 
Spending an evening in the month of June last at Bray, I 
took a walk upon the “ Head,” promising myself, indeed, not 
much of interest (save the beautiful view), from its dry and 
rocky summit. The weather had lately been showery, and 
during the day a considerable quantity of rain had fallen. 
This had left behind small deposits of rain-water in a few 
little hollows amongst the rocks. In one of these tiny pools 
I perceived the water tinged with a beautiful light-green 
colour. A few moments’ inspection, even without alens, was 
sufficient to indicate that this green hue was due to the pre- 
sence of myriads of some “ volvocinaceous ” plant; and with 
alens I soon perceived, by the annular and band-like green 
portions of the organisms, as they appeared under so low an 
amplification, alternately brought to view, that I had had the 
good fortune to encounter that seemingly rare organism, 
Stephanosphera pluvialis (Cohn), which Professor Cohn 
journed from Breslau to Hirschberg to see, and for the occur- 
* Read before the Natural History Society of Dublin, May 6, 1863. 
