340 Dahlia Microscopical Club. 



February 19, 1880. 



A Verticilliiim on Polyporus versicolor. — Mr. Pim showed a 

 species of Verticillium which grew in great quantities on decaying 

 Pohiporus versicolor on stumps in a cold fernery at Monkstown. As 

 he could not satisfactorily determine the species, he sent specimens 

 to the llev. J. E. Vize, who said he believed it to be Polyactis vera. 

 Mr. Pim, however, thought it rather a true Verticillium, most 

 probably Y. epimyces, B. Br. 



Structure of Siphon of Mya areuaria. — Prof. H. W. Mackintosh 

 exhibited two sections of the siphon of the common Lamellibranch 

 Miia arenaria, one being median, the other distal. Both showed a 

 large amount of muscular tissue, the circular fibres being few in the 

 median, but well marked in the distal part. The septum between 

 the two tubes was composed of a band of connective tissue, which 

 at each end radiated out and formed a network, enclosing in ita 

 meshes the bundles of muscle. At each extremity of the septum 

 were placed a large blood-vessel with a nerve on each side. The 

 external surface was composed of a layer of epithelium containing 

 large masses of black pigment-cells corresponding to the periostra- 

 cum ; outside this was a layer of gelatinous substance presenting a 

 stratified appearance, most probably consisting of mucus. The distal 

 section showed that the siphonal tentacles began as processes of the 

 walls of the tubes, which became longer as the orifice was ap- 

 proached. Their first beginnings could be detected some distance 

 down in the tube. Both Rutherford's carmine and llanvier's picro- 

 carmine had been used ; but the former gave the better results. 



Sections of Calculi. — Mr. B. Wills Eichardson exhibited two 

 sections of calculi : one was an excellent specimen of oxalate- 

 of-lime calculus, and probably had its source in the kidney ; the 

 other was one of several passed at intervals, and evidently came 

 from the prostate, the symptoms pointing to that origin. The sec- 

 tions were made by Mr. Baker of London. The longest dia'meter 

 of the oxalate-of-lime calculus was ^ inch, and of the phosphate- of- 

 lime -r\ inch. 



1 O 



Staurastrum hrasiUense, Lundell, new to Ireland. — Mr, Archer 

 presented examples from Connemara (two only, all he had 

 seen) of that noble form, Staurastrum hrasiUense, Lundell, non 

 Nordstedt. Lundell, in the text, gives expression to the supposi- 

 tion that this fine species, as regards the arrangement of the endo- 

 chrome, presented a state intermediate between the central and 

 parietal mode, or rather, as it were, uniting those two types. Mr. 

 Archer had satisfied himself, on getting a good end view of a quite 

 fresh example, that such is not the case, as the endochrome radiates 

 in double plates from the centre towards the angles — in a word, 

 agreeing with the type presented by the majority of Staurastra, and 

 not at all with the parietal arrangement, such as occurs in S. tumi- 

 dum &c. Mr. Archer could hardly acquiesce in the opinion that 



