DUBLIN MICROSCOPICAL CLUB. 213 



composed of thin, shapeless laminae, yet superposed so as to pro- 

 duce a tolerably smoothly outlined margin. The test-opening 

 very large, presenting a broadly-arcuate curve, and forming a 

 rather broad, smoothly margined, band-like border, of a pale yel- 

 lowish colour, or sometimes nearly colourless, thus of a different 

 texture and appearance from the rest of the test. It occurred to 

 Mr. Archer that probably the actual shape of the test was spoon- 

 shaped, that is to say, convex on one side and concave on the 

 other. But as he had seen only empty tests this might be due to 

 a collapse of one of the front, or broad, surfaces. For the same 

 reason it may just possibly be premature to refer this form to 

 Difflugia at all ; but still there could hardly be a doubt but that 

 when specimens with the soft sarcode body may turn up, they 

 will show the characteristics of that genus. 



Oriffitlisia setacea. — Dr. E. Perceval Wright, in continuation 

 of his remarks upon the structure of this Alga, showed a series 

 of preparations exhibiting the formation of its filaments, which 

 were generally described as monosiphonious and articulate. In 

 its young condition, however, the filament did not break up into 

 articulations, and even when it did there was a union through 

 means of a linear series of pores kept up, and only in very ad- 

 vanced joints indeed were these pore-openings closed by • stop- 

 pers.' Carl Niigeli long ago pointed out the existence of these 

 pores in Polysiphonia, but Dr. Wright in addition showed in these 

 specimens the origin of the pore-system, its development and its 

 obliteration, and suggested that it formed a connective tissue, 

 which was found not only in Griffithsia and Polysiphonia, but 

 would be found in other so-called Siphonaceous Algas. 



Monad-form, prohally undescribed, exhibited. — Mr. Archer 

 drew attention to a Monad-form, which, occurring as it does 

 habitually in pairs, or rather twins, did not seem to be noted. 

 This character would seemingly distinguish it from Glenomorum 

 tingens, which the monads themselves somewhat resembled. The 

 truncato-cylindrical pairs of monads hung together, joined by 

 their posterior end, biciliated at the other extremities ; they 

 flitted up and down in a fidgetty manner, now one way, now 

 the other. The eye-speck, so to call it, was here much diffused, 

 that is, the red- or garnet-coloured pigment-granules were 

 scattered, but at same time clustered more at the distal or apical 

 extremities, so as almost to appear as but a single red spot under 

 a low power. This is rare, a denizen of the bottoms of the deep 

 old bog-pools in the County Westmeath. 



December 20th, 1877. 



Further remarJcs on Spine of Atnblypneustes ovum. — Mr. Mack- 

 intosh exhibited further sections of the spines of Amblypnestes 

 ovum, Lamk., which showed that, though this species has,'for the 

 most part, spines with a central axis of reticular tissue, still they 

 are sometimes hollow and surrounded by a ring of calcareous 



