DUBLIN MICROSCOPICAL CLUB. 107 



Dublin coast, and the present specimen was noteworthy on 

 account of the absence of the nematophores generally placed 

 above the thecae, only possessing those in the axils of the pinnae, 

 and one under each cup for the hydranth. 



Epichloe tijpliina, shown. — Mr. Pirn showed sections of Epi- 

 chloe iyphina investing stems of Dactylis gJomerata, gathered 

 near Clonmel. This was the first time he had met with this 

 curious parasite. 



Didymium farinaceum, exhihited. — Dr. W. M. A. "Wright 

 showed examples of Didymium farinaceum from Powerscourt, 

 where it had occurred abundantly on sticks, rotten leaves, &c. 



Botryococcus Braunii. — Dr. Moore showed Botryoeoccus 

 Braunii, remarkable for the vast quantities in which it had 

 occurred in Lough Bray. It is a common production here and 

 there in moorland localities. 



Crystals of Phosphorus shown, and their mode of preparation — 

 Mr. E. J. Moss showed crystals of phosphorus. These were 

 obtained by enclosing small sticks of phosphorus in glass tubes, 

 which were then carefully exhausted by means of the Sprengel- 

 pump and hermetically sealed. The tubes having been enclosed 

 while in opaque cases, fitting closely and blackened at the ends 

 surrounding the phosphorus, were exposed for some weeks to 

 diflused day-light. The phosphorus sublimed and condensed on 

 the sides of the tubes in crystals of remarkable beauty. Some 

 of them, which were complex forms of the cubic system, were 

 nearly 3 mm. in diameter. Owing to their great transparency 

 and the high refractive index of the phosphorus, the crystals 

 exhibited very brilliant colour-effects when strongly illuminated. 



Antheridia in Griffithsia. — Dr. E. P. AVright exhibited and 

 called attention to some preparations of the antheridia in 

 Griffithsia setacea, Ag. Harvey describes the antheridia in this 

 species as " minute oval bodies composed of dense whorls of ex- 

 ceedingly minute glassy filaments, which frequently occupy the 

 place of tetraspores in the involucres." It is not at all easy to 

 understand this description. 



Dillwyn seems never to have seen either tetraspores or anthe- 

 ridia on this species. 



Derbes and Sober, in their elaborate description of the fruc- 

 tification in Griffithsia sphceriea, assert that in this genus the 

 spores, antheridia, and tetraspores are all borne on separate 

 plants, and describe the antheridia as the products of a terminal 

 cell, which divides into a number of daughter-cells, which, before 

 arriving at maturity, generally force asunder the cell-wall of the 

 mother- cell, and then present the appearance of a cluster of 

 grapes on the summit of a stalk, each daughter-cell discharging 

 its contents as an autherozoid form. On this subject Agardh 

 throws no light. 



The specimens exhibited, however, show that the tetraspore- 

 sacs and the antheridial-saes are in this species — the typical one 

 of this genus — borne on the same involucre ; that this involucre 



