16 48 Proceedings of the Royal Irish Academy. 



Another Sphagnum-pool, chiefly S.plumosum, Clare Island, yielded a very 

 mixed association, no species showing dominance: — Tetmemorus granulatus, 

 T. Brebissonii, T. laevis, Netrium Digitus, Staurastrnm sexcostatum, Euastrum 

 dubium, E. denticulntum, E. ansatum, E. Didelta, E. bidentatum, E. binale 

 f. minor, Micrasterias truncata (the last two rather more abundant), 

 M. denticulata, Gosmarium Regnellii (rather frequent), C. pygmaeum, Closteriwm 

 intermedium, (\ Lunula, Eremosphaera viridis, Anabaena Flos-aquae v. minor, 

 Synedra Acus, S. pulchcUa, Vanheurckia rhomboides and its var. saxonica. 

 Navicula Tabellaria, N. mesolepta and its var. Termes, N. viridis, N. major, 

 Tabellaria floeculosa, Eunotia. lunaris, Dinobryon Sertularia, &c. 



A tuft of Microspora abbreviata was examined from Clare Island for its 

 associates ; the three first enumerated were the most abundant ; all are 

 placed in the order of their relative abundance in the gathering : — Gosmarium 

 rectangulare , Chlorobotrys regularis, Staurastrum acicnliferum, Netrium Digitus, 

 Ooeystis snlitaria, Vanheurckia rhomboides v. saxonica, Ulothrix variabilis, 

 (Edogoninm (sterile^, Euastrum binale, Micrasterias truncata, Euastrum 

 bidentatum, Tdmemorus laevis, Gymnozyga moniliformis, Staurastruvi 

 niaiyaritaceum, &e. 



Associated with a submerged species of Hypnum on Clare Island 

 were: — Eremosphaera viridis, Chlorobotrys regularis, Euastrum bidentatum, 

 and Vanheurckia rhomboides var. saxonica, the four together showing 

 dominance; scattered among these occurred, but in much less proportion, 

 Tolypothrix tenuis, Ulothrix variabilis, Binuclearia tatrana, Microspora 

 pachyderma, Gloeocystis gigas, Ooeystis solitaria, Micrasterias truncata, 

 Euastrum binale with varieties, Netrium Digitus, Tetmemorus granulatus, 

 T. laevis, Gosmarium rectangulare, C. tinctum, C. Cucurbita, Spondylosium 

 pulchelliim, Stavrastrum cuspidatum, S. punctulatvm, S. muticum v. minor, 

 Penium didymocarpon, Mesotaenium endlicherianum, Arthrodesmus Incus 

 v. minor, Navicula viridis, N. mesolepta, Tabellaria floeculosa, Merismopedium 

 glaucum, Chroococcus macrococcus, C. turgidus, Oscillatoria Agardhii, Dinobryon 

 protuberans, &c. 



An association consisting of minute algae mostly, from a ditch near the 

 chapel, Clare Island, was thus constituted : — Desmidium Swartzii and 

 Micrasterias denticulata as the main features, the former species more 

 abundant; then the following, all in small proportion, the first three being a 

 little more abundant than the rest : — Pleurotacnium truncatum, Glosterium 

 costatum, C. rostratum, C. pronnm, C. Archeriarnm, Euastrum ablonginn, Penium 

 Navicula, S/drotaenia condensata, Gosmarium subcostatum, C. ochthodes, C. 

 Meneghinii, C. formosulum, G. Botrytis, Mougeotia viridis, Stauroneis 

 Phoenicenteron, S. anceps, Navicula gibba, N. cryptocephala, Surirella robusta; 



