208 M. C. COOKE ON SOME DESMIDS 



There is anotlier closely allied "species in the Capel Curig gather- 

 ing, nearly of the same size, which I have been unable to refer to 

 any described species. The general appearance is more like Stau- 

 rastrum furcigerum, starved and reduced to three arms per cell. It 

 has been determined to call it Staurastrum anatinnm ; Professor 

 Nordstedt professes to be unable to refer it to any described species. 

 Enough has been said already to show what a single gathering from 

 a good locality may produce. 



Nine species of Staurastrum, new to Britain, have been deter- 

 mined, of which six had previously been recorded in Ireland.* 



Staurastrum arctiscon. 



„ oiihiura. 



,, Sehaldi. 



„ cerastes. 



„ aversion. 



,, longispinum. 



And three quite new to the British Isles : — 

 Staurastrum brasiliense. 



„ grande. 



I have intentionally confined myself to the species of Stau- 

 rastrum, as being a sufficient number for which to draw the 

 diagrams, which are all to an uniform scale of 5000 diameters. 

 Incidentally I may mention that the accompanying list contains the 

 species found in the gathering — some very rare and some new — but 

 the whole of the gathering has not yet been exhausted. 



LIST OF THE DESMIDIACE^ FOUND AT CAPEL CUKIG BY 

 A. W. WILLS, ESQ. 



* The asterisk (*) denotes the species which are new to Britain. 



Aptogonum desmiclium, Ehr. Micrasterias pinnatifida, Kutz. 

 Bamhusina Borrei'i, Ealfs. „ radiosa, Ag. 



Didijmoprium Qrevillea, Kutz. ,, dentictdata, Brcb. 



Desmidium SwaHzii, Ag. Uuastrinn vevrucosum, Ehr. 

 Hijalotheca dissiliens, Sm. „ 7;ecii?iati«)?, Breb. 



SplifZ-rozosma vertebrntum, Breb. ,, didelta, Tnrp. 



* „ pitlcheUum, Archer. ,, ansatum, Ehr. 



Micrasterias furcata, Ag. ,, crasstnn, Breb. 



„ 2^apillifera, Breb. ,, binale, Tiirp. 



* Others have been determined since this communication was read, which 

 will be found in an Appendix. 



