PROCEEDINGS OF SOCIETIES. 



Dublin Microscopical Club. 



20th April, 1876. 



On a hitherto unnoticed prohlematic and presumahly parasitic 

 unicellular growth in the cavity of the Cells of Blodgettia, Harvey. 

 — Professor E. Perceval Wright drew attention to another pre- 

 sumably parasitic growth in the cavity of the cells of " Blodgettia " 

 (Harvey), consisting of colourless thick-walled cells. Occurring 

 more or less in rows, and sometimes giving the appearance as if 

 connected by linear stipites, these virere wholly distinct from and 

 far smaller than the presumed spores of Harvey's Blodgettia. If 

 these latter really belong not thereto, but are a foreign parasite 

 (the question raised by Dr. Wright at last meeting of the Club), 

 then one and the same " Cladophora " would seemingly be the host 

 of two distinct parasitic growths. If, on the other hand, fresh 

 examples should hereafter demonstrate the tenability of Harvey's 

 genus, then at least it would seem to harbour the growth to which 

 Dr. Wright to-night drew attention. The crystals described and 

 figured by Harvey were also pre.^^ent. 



Diatomaceous forms from Rockett River, Sierra Leone, were 

 exhibited by Rev. E. O'Meara, who directed attention therein to a 

 form of Coscinodiscus strongly resembling C. perforatus, but dif- 

 fei-ing in having the hyaline areoles around the hyaline centre 

 cuneate instead of round. 



Structures of the leaves of Rimes (Rseudotsuga) Douglasii 

 (= amabilis, Parlatore). — Professor W. R. McNab exhibited sec- 

 tions of the leaf of the Pine collected in New Mexico by Fendler, 

 and numbered " 829." The specimen was from the Herbarium of 

 Trinity College, Dublin, and had been placed at his disposal for 

 examination by Professor Perceval Wright. Parlatore refers this 

 plant to his amahilis, but Dr. McNab considered it to be Rinus 

 (Pseudotsuga) Douglasii. In the parenchyma of the leaf were 

 well-developed idioblasts, sometimes -g'^" across. The idioblasts were 

 stellate cells with many arms, and having the walls very much 

 thickened. The enlarged thickened cells are chiefly arranged on 

 each side of the fibro-vascular bundle forming the midrib, but were 

 not limited to that locality. Dr. McNab has met with similar 

 cells in all the wild specimens of Rinus Douglasii he had examined, 

 but had not been able to detect them in cultivated plants. 



Section of Quartz-rock from Shankill, Co. Dublin, exhibited. — 



