i897-] Proceedi7igs of Irish Societies. 247 



they become more prominent and surrounded with a hyaline ring ; and 

 in later stages the buds are divided by transverse or longitudinal septa, 

 and root-hairs are developed. At this stage the connection with the 

 parent plant becomes very limited, and finally they fall off, and under 

 favourable circumstances reproduce the plant. It may be of interest to 

 note that this mode of reproduction is not to be confounded with the 

 gemmae borne in groups on the apex of stems in Kantia, Cephalozia 

 denudata and Jungermania ventticosa, &c., but, like those of Sendtnera 

 Juniperina, described by Dr. R. S^ruQ.^, Fhytologist, vol. ii., 1885, p. 85, and 

 Mr. M'Ardle's own description, Irish Naturalist, vol. vi., 1895, 

 late 3, of Lejeunea serpyllifolia, they invariably form plantlets with stem 

 and leaves before being separated from the parent plant. 



Prof T. Johnson exhibited a preparation of Cotnatricha Persooniiy Rost., 

 a slime-fungus found among dead leaves. The preparation was one of a 

 set of specimens, illustrating nearly a hundred species of the British 

 Mycetozoa (Myxomycetes or Slime-fungi) recently presented to the 

 Botanical Collections of the Dublin Science and Art Museum, by A. 

 Lister, V.RL.S., by whom the Catalogue of the group was prepared for 

 the Trustees of the British Museum. 



Mr. Ai,i,AN Swan sent for exhibition a mounted cultivation of 

 Cladothrix dichotoma, and a species of Achlya which appears identical with 

 de Barig's Achlya polyandra. These two forms were grown together on a 

 cover glass cultivation for identification purposes ; Cladothrix appears with 

 the very characteristic short rods and spores which have broken up from 

 the long twisted filaments of earlier growth ; Achlya shows only the 

 earliest stages of development, with no sign of spore-formation, and the 

 protoplasmic contents of the hyphae has been injured by drying. C. 

 dichotoma is one of the commonest of fresh-water organisms, it flourishes 

 whenever organic impurity is present, and if traces of iron be present in 

 the water, its massed filaments have a marked red colour, which can be 

 shown to be iron by the ferrocyanide of potassium test ; Achlya and allied 

 forms of the Saprolegniese are much more common in our water supplies 

 than is generally supposed. The exhibitor has never failed to find them 

 after a proper search. These two forms of life are generally to be found 

 on submerged animal or vegetable matter in streams or ponds, but he has 

 lately found them flourishing luxuriantly in air-exposed situations, with 

 restricted water supply, and taking their nourishment entirely in the 

 soluble form, from an impure water which was only sprinkled or be- 

 spattered over them, as they grew side-by- side on a perpendicular wall 

 near a sewer grating. The identification of C. dichotoma is a simple matter 

 as it is easily cultivated, and its characteristic red colour (which formerly 

 caused it to be called Leptothrixochracae) can be shown to be an iron oxide. 

 The Achlya forms by quite recent investigation are shown to be more 

 numerous than were formerly supposed, for this reason the exhibitor is 

 unable to identify the species, until he can consult the latest work on the 

 subject. The form here shown is easily cultivated on flies, and its two 

 forms of spores more readily produced, the zoospores are non-motile, 

 and after liberation remain grouped at the mouth of the sporange ; with 



