tgi2. Irish Societies. 241 



DUBLIN MICROSCOPICAL CLUB. 



October 9. — The Club met at Leinster House, J. H. Woodworth 

 (President), in the Chair. 



N. CoLGAN exhibited dermal deposits of two Holothurians taken off the 

 Dublin coast, Cucumavia lactea and C. Hyndmanni, both dredged in 16 fms. 

 off Church Island, Skerries, on the 13th July last. The first species 

 which includes Ocnus brunneus and O. lacteus of Forbes's " British Star- 

 fishes," appears to be the commonest holothurian of the Dublin coast. 

 In three dredgings off Skerries in July last, 10 specimens of the brown 

 form (0. branneus) were taken, and 6 others were dredged in 5 fms. in 

 Dalkey Sound in August, 1906. The white form is much rarer. It was 

 only once taken by the exhibitor, who dredged two small specimens 8mm. 

 in length in 8 fms. off Bullock in September last. The deposits of this 

 species as exhibited agreed perfectly with Bell's plate in his " Catalogue 

 of British Echinoderms," 1892 ; but in the case of the much rarer C. 

 Hyndmanni, which has been only once previously recorded for Dublin 

 waters, the body deposits were in general quite different from those given 

 by Bell, although the deposits from the podia or sucker-feet were precisely 

 as those he figures. The body deposits in the Skerries specimen, which 

 was 2f inches long, formed a dense stratum in the glistening white epidermis 

 between the five equidistant rows of crowded suckers, and were oblong 

 ovate in form ; they were solid, not flattened, and marked by numerous 

 deep indentations, none of which amounted to true perforations. In 

 general aspect these deposits strikingly resembled oblong potato -tubers 

 with frequent " eyes." Canon Norman in his paper on Ciicumaria Montagui 

 {Ann. and Mag. Nat. Hist., 1905), has shewn that the body deposits in 

 mature C. Hyndmanni are thick and nodular as those exhibited and 

 quite unlike those figured by Bell. Amongst the characteristic nodular 

 body deposit of the Skerries specimen, an occasional flat perforated plate 

 appeared similar to those in Bell's figure. 



D. McArdle showed a remarkable form of Dicranella hctcromalla 

 Schimp. which was sent to him by H. N. Dixon, F.L.S., of Northampton, 

 and forms the subject of an interesting article in the Journal of Botany. 

 October, 19 12, p. 306. The moss was first found growing along the side 

 of a trench on Burridge Heath, half a mile east of Great Bidwyn, near 

 Hungerford, Wilts, and the range was subsequently extended for half a 

 mile. On the slide exhibited was a perfect specimen, showing the foliage 

 like D. heteromalla, but the capsules were quite unlike the normal form 

 of that species which is common in Ireland, native specimens being shown 

 for comparison. The capsule instead of being elongate, brown-coloured, 

 and inclined, on a long straw-coloured seta, was short, small, deep reddish 

 brown, almost erect, and symmetrical, wide mouthed, and on a very short 

 red, often deep red seta, so as to be almost immersed in the tufts, and 

 presented very much the appearance of the fruit of Dicranella varia. In 

 the more erect and symmetrical capsule, the plant comes near the van 

 orthocarpa of Hedwig. 



He also exhibited an aquatic form of Eiirhynchiitm riiscifornic Milde, 

 which he found growing in a stream which flows through the Glen of the 



