DUBLIN MICROSCOPICAL CLUB. 463 



became encysted ; and again, the ray-like portions seemed to 

 aggregate together like what is seen in Myxodictyum. 



IWi April, 1877. 



Preparations of monstrous form of 3Iitscari exhibited. — Mr. Gr. 

 Pim showed some preparations of Muscari comosum, var. monstro- 

 smn, in which all the floral organs were converted into long filiform 

 bodies, beset with small protuberances, probably buds, and consist- 

 ing of one or two plates of parenchymatous tissue. This form is 

 permanently monstrous. 



Olpidiiim (Chytridium) tumefaciens, Magnus, exiiihited. — Pro- 

 fessor E. Perceval Wright showed a series of specimens of Olpidium 

 (Chytridium) tumefaciens, P. Magnus, found living in the trichomes 

 and young cells of the thallus of Geramium acanthonotum, collected 

 at Howth. The species had been described by Professor Magnus 

 in the ' Jahresbericht der Commission zur wissenschaftlichen Un- 

 tersuchung der Deutschen Meere in Kiel,' p. 76, t. i, f. 1 — 16. 

 The algse with this parasite were found by Professor Magnus at 

 Fisherrow, near Edinburgh. It was not uncommon at Howth. 

 Chytridium Sphacellarum, Kny, though not exhibited, had also 

 been met with. 



Neiv Species of Coscinodiscus shoion.' — Eev. E. O'Meara exhibited 

 what appeared to him to be an undescribed species of Coscinodiscus 

 found by him in the remarkable gathering by Mr. Moseley, H.M.S. 

 " Challenger," from the surface of the Arefusa Sea. The form is 

 large, diam. O'OIS", however, considerably smaller than the very 

 striking species exhibited at last meeting by Mr. O'Meara under 

 the name of Coscinodiscus craspedodiscus, a comparison with the 

 leading features of which would best pourtray the characteristics 

 of the present. Here the broad margin so remarkable in the 

 former is absent. In the present form, as in it, the radiate lines of 

 areoles terminate some distance from the centre ; the central blank 

 space, however, is much smaller, and the lines of areoles are of more 

 equal length. Areoles of margin subhexagonal, diminishing in size 

 towards the ends ; they are shorter, broader, and much more robust 

 than in Coscin. craspedodiscus. Mr. O'Meara proposed to name 

 the species from the locality where it had been found — Coscino- 

 discus ArafuscBnsis. 



Section of Spine of Echinothrix annellata, Peters, exhibited. — 

 Mr. Mackintosh exhibited a cross section of the spine of Echino- 

 thrix annellata, Peters, specimens of which had been kindly sent 

 him by Dr. Griinther, E.E.S. This species had been united with 

 E. Besorii, Peters, by Prof. A. Agassiz in his recent " Revision of 

 the Echinoderms," but it differs, as far as can be judged, from the 

 present specimens in the total absence of the reticular tissue, which 

 is so conspicuous a feature in the spine of E. Desorii, and in the 

 extremely slender nature of the solid wedges (scarcely deserving 

 the name of wedges), their circumferential being hardly thicker 

 than their central parts. 



