PROCEEDINGS OF SOCIETIES, 
Dustin MicroscorircaL Crus. 
29th April, 1870. 
Rey. Evenne O'Meara exhibited specimens of Gomphonema 
balticwm (Cleve), kindly supplied to him by Herr Cleve himself, there 
being, therefore, no possible doubt about the identity of the form. 
The point to which Mr. O’ Meara wished, however, to draw attention 
was that there existed well-marked transverse strive, as well as a 
central nodule, characteristics which are not described nor figured 
by Cleve, so that his account of this species requires this important 
correction. 
Mr. Archer exhibited several Desmidiez rarely met with, and one 
at least new, taken on a recent visit to Kylemore, County Galway, 
in company with Professor E. Perceval Wright. Amongst these 
was to be noticed Spherozosma secedens (de Bary), a form not yet 
recorded, so far as Mr. Archer was aware, by any other observer, 
nor hitherto detected by himself. Though referred to the genus 
Spherozosma by de Bary, this form belongs properly to de Bréb- 
issons’ genus Spondylosium. On this latter genus de Bary makes 
no further comment in his work (‘ Untersuchungen iiber die Con- 
jugaten ’) beyond simply quoting de Brébisson’s original description 
in Latin (‘ Liste des Desmidiées observées en Basse-Normandie’), 
and adding the remark, “unknown tome.” The minute connecting 
processes between the joints characteristic inSphzrozosma are wanting 
in Spondylosium, and, simple as this distinction may be, it yet seems 
to be of value, and even Dr. Wallich seems to have seen the necessity 
for such a genus when he instituted the genus Leuronema (‘ Ann. of 
Nat. Hist.,’ 3rd ser., vol.v, pp. 186 and 193), which corresponds nearly 
completely with Spondylosium, to which name Dr. Wallich’s must, 
therefore, seemingly give way. It is true, indeed, that some of the 
described forms referred to Leuronema (Wallich) are three-angled in 
transverse view, whilst others, like the known European and British 
forms, are plane. Still, even the three-angled forms could not be 
correctly kept out of the genus Spondylosium on that ground merely, 
just as we have compressed as well as angular species in the genus 
Desmidium, and even in Staurastrum. There could be no doubt of 
the identity of the form now shown with that of de Bary ; if there 
was any difference traceable it would be the slight concavity shown 
in his figure at the top or end of the segments was less expressed in 
the present specimens. 
Another desmid new to Britain, shown by Mr. Archer, from the 
same locality, was the form designated by Prof. Wittrock Stawrastrum 
