92 



fibres are obscurely striated, and, when young, are not only much 

 lighter in colour, but also appear to be hollow. It will thus be 

 evident that but little additional light can be thrown on this 

 curious form, beyond that already thrown on it by Dr. J. E. Gray, 

 until its rediscovery in a recent state ; but Professor Wright 

 trusted that, in exhibiting this specimen and detaining the Club 

 with these remarks, he would not be considered as altogether 

 wasting the time of the members, and he would simply now express 

 his opinion that Ceratellidse was a family of arborescent keratose 

 sponges. 



Mr. Archer showed Cosmarium annulatum (Nag.), seen by him 

 for the second time only. The first occasion was in a gathering 

 made in the " Rocky Valley," near Bray, and the present was made 

 from pools near Mullingar; but as the species is very minute, it 

 may have been overlooked in other localities. 



Mr. Archer wished to record that he had since had an opportu- 

 nity to make some collections from the same locality in County 

 "VVestmeath from which Dr. Barker had obtained the remarkable 

 plane form exhibited at the July meeting, which he (Mr. Archer) 

 w^ould refer to Staurastrum gracile, and that he had met with 

 the triangular form, as well as the plane, in one of the gatherings, 

 thus, he thought, fully bearing out the forecast he had made, 

 and the views he had expressed ; at least, so far as could be 

 done pending the discovery of the zygospores, but which, indeed, 

 might just possibly tend to decide the question in the other di- 

 rection. 



Mr. Archer likewise showed Characium tenue (Hermann). 



Mr. Archer further drew attention to some extremely minute 

 bodies of a crystalline appearance, occurring inside the cells of 

 Spirogyra nitida. These floated just close under the spiral bands, 

 presented a greenish hue, and were of a general cruciform or X 

 figure, the arms very slender, and sometimes branched or fea- 

 thered more or less ; sometimes an H figure, with the horizontal 

 connecting line produced beyond the vertical ones at both sides ; 

 the extremities, as in the cruciform ones, likewise somewhat 

 branched. These were clearly not chlorophyll-granules, though 

 showing a greenish tint. 



Dr. Moore showed a gathering of the little minute unicellular 

 clustered alga which sometimes forms a scum on the surface of 

 the waters in the houses at the Botanic Gardens, drawn attention 

 to by him at the Club meeting of July, 1S66. The identity 

 or naming of this production would, however, be a matter of 

 great diOiculty, but it was interesting to note its periodic re- 

 currence. 



Mr. Archer drew attention to a puzzling production he had 

 lately noticed in some quantity in the gatherings made from pools 

 near Mullingar. This consisted of a tabular or foliaceous, very 

 variously shaped, frond (so to call it), composed seemingly of 

 bacillar greenish bodies, held together in close approximation 

 and in variously arranged positions, but so as to leave no irregular 



