HARDWICKE'S SCIENCE-GOSSIP. 



113 



British ferns ; certain roots and stumps of trees in an 

 advanced state of decay being built in amongst the 

 stone. Early in the spring of 1S75 a number of 

 minute, beautifully-formed bodies made their appear- 

 ance on one of the stumps, resembling very small 

 round-headed pins pricked into the wood. They 

 were pulpy in consistence, and of a lemon-colour, 

 which gradually deepened into a brown, and then 

 assumed a metallic steel-grey lustre, their interior 

 being full of spores and threads. On investigation 

 these were found to be fungi of the Myxogastric 

 family, and geuus Didymium. In the month of May 

 he noticed upon the same stump some small masses 

 of a white substance resembling blanc-mange, 

 irregular in form, as though dropped there out of a 

 spoon. Three hours later the surface of the sub- 

 stance had assumed a vein-like appearance, some- 

 what swelled and interlacing, which soon changed 

 to regularly formed granulations; the mass also 

 seemed to have moved its position on the stump, 

 leaving behind it a peculiar slimy substance. A visit 

 a few hours later showed a complete transformation, 

 for the whole mass, with the exception of the slimy 

 film, appeared to be lifted bodily up, aud supported 

 underneath by numerous closely-packed horse-hair- 

 like stems, the mass being thicker and the granula- 

 tions more distinct, whilst the colour was opalescent. 

 In the course of a night it became evident that the 

 granulations were the apices of so many closely- 

 compacted but distinct elongated cells, each of which 

 was supported by one of the before-mentioned stems, 

 and as the mass dried they separated from each 

 other, until they resembled a nodding plume of 

 feathers ; the colour now being dark brown, and the 

 outer membrane bursting, the whole soon became a 

 dusty mass of spores, aud thus the writer made his 

 first acquaintance with Stemonitis fusca. Very 

 shortly after the appearance of the Stemonitis two 

 fresh , forms were observed ; one consisting of 

 minute cylindrical heads standing on stems near but 

 distinct from each other ; they were of the same 

 colour and consistence as the blanc-mange-like mass 

 before mentioned ; in a few hours they turned pink, 

 and finally assumed a bright vermilion colour, and 

 in a few days the rupture of the peridium displayed 

 the elastic threads of the capillitium, which main- 

 tained the same shape as before bursting, but was 

 much increased in bulk, and the vermilion-coloured 

 spores scattered in all directions : this was Arcyria 

 punicea. A cluster of globular bodies about the 

 size of small marbles next appeared, of a beautiful 

 pinkish flesh-colour, which deepened to a salmon- 

 colour, and finally became drab. At first they were 

 full of flesh-coloured liquid, and the following 

 morning a single drop of liquid, clear as water, stood 

 on the crown of each, as though it had excreted, 

 but no rupture was visible, and in a few days they 

 had become filled with spores and threads, which 

 puffed out as the common puff-ball ; this was 



Lycogala epidendron. Other varieties simultaneously 

 appeared, until the number was swelled to eight 

 remarkable specimens, all of which grew within a 

 few inches of each other on the same stump, and 

 represented no less than six genera of the order 

 Myxogastres, the following being £their names : 

 Arcyria panicea, Arcyria nutans, Stemonitis fusca, 

 Lycogala epidendron, Physarum nutans; Didymium— 

 Trichia turbinata, Trichia chrysosperma. 



Report on the Irish Diatomace^e, by the 

 Rev. Eugene O'Meara, M.A. Part I.*— Nearly 

 a quarter of a century has passed away since the 

 appearance of vol. i. of Smith's "Synopsis of the 

 British Diatomacese," and nearly twenty years have 

 elapsed since its completion: from that period 

 until the present time no work has appeared de- 

 scribing systematically the Diatoms occurring in the 

 British islands. Only scattered papers have from 

 time to time appeared in various scientific serials, 

 noting the occurrence of new forms. We were 

 therefore pleased to learn that a report on the 

 Diatomacese of Ireland was in hand, the first part of 

 which is now published. The author has adopted 

 the system of Heiberg {see " Dausk Diatomeer "), 

 which he says " appears to me to have most to re- 

 commend it, founded on the symmetrical or unsym- 

 metrical structure of the frustules in their various 

 aspects. There are two principal aspects in which 

 a diatomaceous frustule may be regarded, — the front 

 view, in which the hoop or connecting band is 

 presented to the eye ; and the side view, in which 

 one or other of the valves is under observation ; and 

 in both these positions the longitudinal and trans- 

 verse axes are to be considered. If in the two 

 positions, and in these varied views, exact symmetry 

 obtains, the frustule is said to be symmetrical in all 

 its aspects, but if the two opposite valves are not 

 uniform, or the portions of the valves on either side 

 of the transverse or longitudinal axis, on a side view 

 or front view, do not exhibit the same proportions 

 or outline, the frustule is said to be unsymmetrical 

 on that view or axis on which the difference of form 

 is observable. Such is the ground-plan of Heiberg's 

 systematic arrangement, and which I have adopted 

 in the present report. It is not indeed wholly free 

 from objections to which other systems are liable, 

 and possibly may be open to others peculiarly its 

 own ; but still the principle on which this arrange- 

 ment is based commends itself as being at once 

 more simple, more comprehensive, and most easily 

 applied." 



The division is certainly open to' the objection 



* Only 100 copies have been reprinted from the " Pro- 

 ceedings of the Royal Irish Academy " (for whom the report 

 was written), and when these are disposed of, no separate 

 copies will be obtainable. At present copies can be pro- 

 cured of the author (price 7s- 6d.), Rev. E. O'Meara, New- 

 castle Rectory, Hazelhatch, Dublin. 



