210 Dublin Microscopical Club. 



presents a club-shaped figure, and occurs seated on Confervoids, at- 

 tached thereto by the base of the attenuated lower prolongation ; it 

 is colourless and hyaline, with the exception of a centrally posed, 

 often subtriangular, green mass, occupying the centre of the more 

 swollen part of the club-shaped hyaline structure. The upper and 

 rounded terminal extremity possesses at the very apex a circular 

 sharply marked foramen, surrounded by a slightly thickened rim. 

 Were a flagellum seen to protrude through this, the organism might 

 be compared to a stipitate or attached form allied to Chlamydomonas 

 &c. ; but not a trace of any flagellum could ever be detected. It 

 must not be at all supposed that this could be a form of Characium, 

 or still less a young one-celled plantlet belonging to either QZdogo- 

 nium or to Chcetophora; such could not for a moment be confounded 

 with the organism, whatever it may be, to which attention is now 

 drawn, the true nature of which must unfortunately remain doubtful; 

 it is probably algal. Although it is rather widely distributed, it still 

 is decidedly rare and in reality but very seldom encountered. 







June 16, 1881. 



Locomotive State of Bacterium rubescens, Lankester, and a com- 

 panion form, likewise active. — Mr. Archer showed that actively 

 moving state of Bacterium rubescens, Lankester, to which he had 

 once before drawn attention, then as probably a new form of Jsageli's 

 genus Ccelosphcerium, in which the globular congeries of cells keeps 

 fitfully rolling about, more or less actively. In this form indeed 

 the appearance of the cells, with their red circumference and blue 

 centre, was precisely that of the (so-called) Bacterium rubescens ; and, 

 as Mr. Archer showed on another slide, it was precisely that of an 

 indubitable filamentous and oscillatoriaceous alga — so much so that 

 the main difference was, in the cells themselves, but one of size, apart, 

 of course, from the quite different mode of build-up of the plant 

 itself in each instance. Doubtless those who hold Bacterium rubes- 

 cens to be truly a Bacterium proper would regard the condition now 

 ihown as the parallel of the glosogenous state of Bacterium termo, 

 only that the mucous matrix is not so strongly developed in the 

 present form ; but the gloeogenous state of B. termo does not move 

 about as an aggregate mass. Here indeed no cilia or flagella what- 

 ever can be detected, nor can any modus operandi of the movement 

 be made out under the microscope ; but this remarkable action all 

 the more strikes the observer with wonder. Mr. Archer was able 

 on the present occasion to draw attention to a companion form for 

 the one just adverted to, one in which the constituent cells were of 

 a wholly different aspect — more minute, more rotund, quite homo- 

 geneous, all over of a very pale phycochromaceous tint, and bound 

 together in little clusters, these, however, often of only, say, four 

 cells up to, say, a dozen or more. Now these were clearly not the 

 same thing as the former ; for in all the phases of B. rubescens the 

 cells evince a resemblance, and seem to maintain their characteristic 

 appearance ; but these little congeries of still more minute cells 



