Clare Island Survey- — Fresh-water Alyae. 10 49 



S. biseriata, and a very small quantity of a barren Oedogonium (Hydra vulgaris 

 was also present). 



A large patch of Cladophora glomerata from the cliffs of Croaghmore had 

 an association of diatoms upon and among it ; the epiphytic Coeconeis Pedioulus 

 was the truly dominant one, and almost hid some parts of the Cladophora 

 from view. The other species occurred in varying proportions, and I have 



written down the chief of them in the approximate order of their frequency : 



Cocconema gastroides, C cymbiforme, C. Navioula, C. Brebissonii, Epithemia Sorex, 

 E. zebra and its variety proboscidea, E. Ryndmanni (small forms), Eimotia 

 Arcus v. minor, Syneclra Acus, Gomphonema gracile v. dichotomum, Achnanthes 

 wilis, Cocconema ventricosum, Diatoma elongatum, Navicida gracilis, N. viridis 

 (small forms), Nitzschia Sigma v. rigida, Synedra Ulna, Gyrosigma Spencerii 

 v. nodifera, Stauroneis anceps, &c. 



Near Dugort, Achill Island, associated in a pool along with Batracho- 

 spermum vagum were Euastrum bidentatum and Spondylosium pidchcllum in 

 fair quantity ; next in point of numbers came Desmidium cylindricum and 

 Opliiocytium cochleare, then in less quantity Oocystis solitaria, Chlorobotrys 

 regularis, Mougeotia (sterile), Oedogonium (sterile), Vanheurckia rhomboides 

 v. crassinervia; after these, and quite scattered, were Penium Digitus, P. 

 Navicula, Tetmemomos granulatus, Closterium Lunula, C. juncidum, C. acutum 

 var Linea,Staurastrummargaritace%un, S. tetracerum, S.paradmum, Cosmarium 

 pygmaeum, C. subtumidum, C. pyramidatum, Euastrum ansatum, E. binale, 

 Micrasterias truncata, Hyalotlieca dissiliens (with zygospores), Eremosphaera 

 viridis, Merismopedium glancum, Tetrapedia reinschiana, Chroococcus minutus, 

 Tabellaria fiocculosa, Nitzscliia Palea, iV". subtilis, Navicida Brebissonii, N. 

 viridis, N. nobilis, Vanheurckia rhomboides, &c. 



An association near the summit of Croaghaun, Achill Island, 2,192 feet 

 elevation, consisted of the following in a very mixed manner, no species 

 approaching either dominance or subdominance : — Mougeotia (sterile), 

 Oedogonium (sterile), Batrachospermum vagum, Bimiclearia tatrana, Microspora 

 abbreviata, Oocystis solitaria, Scenedesmus obliquus, Chlorobotrys regularis, 

 Arthrodesmns octocornis, Staiirastrmn parudoxum, S. tetracerum, Closterium 

 intermedium, Cosmarium tatricum, C. Cucurbita, C. Phaseolus v. elevatum, 

 Euastrum binale, E.dentic datum, Navicula viridis, N. Brebissonii, Vanheurckia 

 rhomboides v. saxonica, Eunotia lunaris, &c. 



Associated in a scattered manner with Bidboclmete insignis in Lough 

 Gall, Achill Island, were: — ITapalosiphon hiberniciis, Lyngbya Eirulariarum, 

 2 sterile species of Spirogyra, 1 of Zygnema, 2 delicate species of Oedogonium. 

 (one was not more than 3'3/i in diameter, and might be either inconspiev/um or 

 excisum; the thickest specimens of the other were 5ju broad, the size of 



R.I.A. fBOC, VOL. XSXI. G 16 



