DUBLIN MICROSCOPICAL CLUB. 237 



quadratic general figure, but rounded at upper angles, and the 

 constriction forming a rounded sinus at each Bide, the upper 

 margin continuously with the "angles " broadly and gently con- 

 vex, length and breadth about equal. It was thus different from 

 any (British) Cosmarium. Never was a more deceptive little 

 form, for it was not a species of Cosmarium at all, though, with- 

 out doubt, desmidian. Some examination of the slide, indeed, 

 soon showed that this quasi-Cosmarium owed its origin to an ex- 

 ceptional state of an Jrthrodesmus-incus-iovva, that minute one, 

 in fact, with simple cuneiform semicells and spines very slightly 

 divergent. As is well known, when the growth of the new semicell, 

 subsequent to division, is but partially advanced, the spines are 

 not yet produced and the angles bluntly rounded; at this point, 

 in several cases, the new semicell, as regards its own growth, had 

 remained stationary, but, that notwithstanding, self-division had 

 once more set in and new semicells were formed, the result of this 

 second generation being these pseudo-Cosmaria. Here was a 

 case, some might be found to advance, of the direct "jump " of 

 one species into another " new " one ! But it was not so. Cases 

 were to be seen on the slide where some of these examples, which 

 at the proper epoch had neglected to develop the spines, were 

 now trying, as it were, to make up for lost time, and young short 

 spines were at one end making their appearance. The whole 

 thing was thus a mere " sport " — still a puzzling case of excep- 

 tional growth, such as Mr. Archer believed had not been before 

 noticed, and therefore worthy of a passing record. 



Euglypha spinosa, Carter, exhibited. — Mr. Archer, on the part 

 of Mr. Crowe, who had taken the example in North Wales, ex- 

 hibited Euglypha spinosa. Carter, a fine and large species, and 

 most marked ; it appears very rare indeed ; as yet in Ireland it 

 has only been found in Co. Kerry, and at " Toole's Eocks," Co. 

 "Wicklow, by Mr. Archer. 



"Headed^^ Bacterian exhibited and note thereon. — Mr. Archer 

 showed the active, and the stillgloeogenous " Zoogloea " condition of 

 a bacterian seemingly very close to the " headed " form figured by 

 Cohn in his memoir in his ' Beitr. z. Biol. d. Pflangzen,' Heft 2 

 (1872), t. iii, f. 13, though the actual identity seemed to be at 

 least doubtful. Cohn's examples occurred in an infusion of dead 

 flies ; on the other hand, the present occurs in quite fresh gather- 

 ings where all around — desmids, diatoms and other algae, infusoria 

 and rotatoria, &c. — are in quite active and healthy condition. 

 Hence Mr. Archer ventured to suppose, at least ad interim, that 

 it could be hardly correct to relegate such forms as this, of local 

 occurrence (and quere also Prof. Lankester's B. rubescens), and 

 which live and flourish in seemingly only healthy environments, 

 to one of the same gemis as the common and universal forms of 

 putrescent or decaying, often stinking, infusions. The long and 

 slender little filamentary bodies combined in a manner approxi- 

 mately parallel, in 4'8 and 8's, or sometimes in 16's, within their 

 common oblong or ovate, definitely bounded mucous matrix, might 



