164 DuIjUh Microscopical Club. 



These were found in consideral)]e numbers adhering to the outside 

 of the conceptacular portion of the thallus. The embryos measured 

 about yI-jj inch, but some were as long as yi-g- inch, and notched at 

 the apex, where a few hairs also originated. The specimens were 

 collected on the shore at Clontarf on the morning of the ISth June. 

 It seems therefore that the youug embryos adhere for a short time 

 to the surface of the mature thallus after their escape from the 

 couceptacle. 



Olivine Dolerite. — Prof. Hull, F.R.S., exhibited a thin section of 

 Olivine Dolerite from Balletitory, co. Antrim. This rock is very 

 massive and is quarried by the Eglinton Mineral Company for 

 paving sets. Under the 2-inch objective it is seen to consist of 

 plagioclase, augite, olivine, and titaniferous magnetite, the last not 

 abundant. The effect with the polariscope is very fine, the olivine 

 being fresh and polarizing vividly. 



Toung Parasitic State of Halcampa. — Prof. A. C. Haddon exhi- 

 bited a living immature sea-anemone which was parasitic on Hydro- 

 medusse. It was a still younger example than that described by 

 Eeid as Halcampa Falioni, which Prof. Iladdon believed was 

 the voung form of Halcampa clirysanthellum, Peach. Recently 

 Mark has described the young of an Edwardsia as parasitic on the 

 ctenophore Mnemiopsis Lcichji, so there is nothing unique in the 

 parasitic habits of a larval sea-anemone. 



Continuitu of Protoplasm in Facus. — Mr. Greenwood Pim exhi- 

 bited sections of Fucas vesicidosus in which the continuity of the 

 protoplasm from one cell to another was clearly shown. The sec- 

 tions were prepared in accordance with Dr. Hicks's directions in the 

 April number of the ' Journal of Botany ' — soaked in sulphuric acid 

 and water (1 : 3), stained with safFranin, and mounted either in pure 

 glycerine or glycerine and ammonia. 



Zygospore of Cosmarium corbida, Breb.^ — -Mr. Archer showed the 

 zygospore of Cosmarium corhida, Breb., orbicular, and beset with 

 rather numerous, elongate, slender spines, trifid at apex ; this is 

 rather a rare species, and still more rarely found conjugated. 



October 15, 1885. 



Rhizopodal Parasite (?) in a Sponge. — Prof. Sollas exhibited a 

 section of a sponge having imbedded therein, seemingly occupying a 

 cavity, an orbicular body, presenting many features giving it a 

 strong resemblance to some rhizopodal form, showing what appeared 

 to be a median nucleus and seemingly elongate pseudopodia. It 

 did not seem to offer a resemblance to any state of an ovum. 



Gloiotrichia natans exhibited. — Prof. M'Xab exhibited examjjles of 

 Gloiotrichia natans which had develo])ed in quantity in one of the 

 tanks in the College of Science amongst plants which had been 

 brought in June from the pond in the Botanic Gardens, Glasnevin. 



