252 The Irtsh NaturalisL December, 



October 13. — The Club met at Leiuster House. Dr. G. H. Pethy- 

 BRIDGE (President) exhibited the fungus Verticiliinn alboatrian, Reiuke et 

 Berthold, which he had obtained by culture from potato plants growing 

 near Dublin attacked with one of the forms of •' leaf-curl " or " roll." 

 The fungus is of very considerable economic importance, and this is the 

 first time it has been recorded for the British Islands. The wood vessels 

 of everj' part of the attacked plants, leaves, stems, roots and rhizomes, 

 were permeated by the mycelium of this fungus, and it also enters the 

 tubers, having been traced in one instance to a distance of two and a halt 

 inches from the heel end. Owing to the choking of the vascular system 

 of the plant it wilts and dies, and the fungus then spreads into other 

 tissues than the wood and destrojs them. The mycelium then becomes 

 black and passes into a hibernating condition, and is capable of renewing 

 its growth again in the following season under suitable conditions. 

 Healthy potato plants can be art^ficiallj' inoculated with the fungus 

 through wounds. In one such case the mycelium travelled up the stalk 

 in the wood vessels to a distance of about eight inches in the course of 

 a few weeks. How infection occurs under natural conditions in the 

 field is not known wnth certaint}', but planting affected "seed" would 

 seem to be one means of propagating the disease. Further experiments 

 with this fungus are in progress. 



J. N. Halbert showed the larval and adult forms of the hemipteron 

 Nobis lativentris, found commonly under clumps of Matricaria, &'c., on 

 the south shore of Howth. The larva of this species is 'highly chitinised 

 and well pigmented with dark colour, and in general structure bears a 

 superficial resemblance to the common black ant Fortuica fusca, which 

 abounds in the same locality. The resemblance between the two insects 

 was especially' striking when they were seen rimning about in company. 

 The hemipteron is apparently common in England, but in this country 

 it is rather local, occurring chief!}' in maritime localities. 



R. Southern exhibited a living specimen, with tube, oi Lanicecoiuhi- 

 lega (Gall.) The tubes of this polychaete, with their opercular flaps 

 fringed with long filaments, are amongst the commonest sights of the 

 littoral region. The tubes penetrate into the sand for a considerable 

 distance, and hence the worms are seldom seen. The specimen exhibited 

 •was obtained from a rock-pool at Howth, Co. Dublin. 



F. W. Moore exhibited the fructifying stage of Stevionitis ferrtiginea, 

 one of the Myxomycetes. It was found growing on a damp shaded bank 

 in the Botanic Gardens. The plasmodium stage covered a large space, 

 adhering to leaves of grass, Campanala, and dead H0II3' leaves, soft j'el- 

 lowish irregular plastic masses. The sporangia were dark brown on 

 short stalks. 



