ON SCOTTISH DESMIDIE^ 243 



CLOSTERIUM, Nitzsch. 



1. C. acerosum (Schrank), Ehrb. Widely distributed, but scarce. 



/3 Ralfs. - - Rare. Aberdeen -- Little Don, Alford, and 

 Achnerran, Cromar ; Kincardine near Caterline, 

 in brackish water ; Forfar Balquhadly Hill, Fern : 

 Renfrew near Greenock. 



2. C. adculare, West. Very rare. Ross near Tain; Aberdeen 



Dinnet Moss, plentiful. 



3. C. acittum (Lyngbye), Breb. Pretty common. With zygospores 



at Craigendinnie in Aberdeen ; Kincardine on Kerloch 

 and near Portlethen. (See under C. tinea.} 



4. C. angustatum, Kg. Not common. Sutherland, Ross, Inver- 



ness, Aberdeen, Kincardine, Forfar, Perth, Stirling, Argyle, 

 Renfrew, Kirkcudbright. 



S-^C. angiistiim, Hantzsch.- -Very rare. Aberdeen near Slains 

 Castle, Bourtie, Little Don at Haughton Alford. 



6. C. antiacerosuin, De Notaris. Apparently very rare ; perhaps 



overlooked. Aberdeen Whitestripes Moss near Aberdeen, 

 marsh west from the Ord near Dinnet. 



7. C. Archerianum, Cleve. Somewhat rare. Ross near View 



Rock, Strathpeffer ; Aberdeen Scotston Moor, Brimmond, 

 moss on Skene Road, Powlair, Forest of Birse, Slewdrum, 

 Birsemore, Black Moss, Birkhill, and Presswhin in 

 Cromar ; Kincardine Raemoir, Cammie ; Forfar Barrel- 

 well near Brechin, Findhaven Hills, Glen Clova ; Perth 

 Durdie Moor ; Stirling Fintray Hills ; Argyle near Kings- 

 house. 



8. C. arciiatum, Breb. Not common. Sutherland, Ross, Inver- 



ness, Aberdeen, Kincardine, Forfar, Perth, Fife. 



With zygospores at Fyvie in Aberdeen, and Cammie in 

 Kincardine. They are globular, 27-29 p in diameter; con- 

 jugating fronds crossed. 



9. C. attcnuatiim, Ehr. Widely distributed, but not observed in 



the following counties : Orkney and Shetland, Caithness, 

 Sutherland, Nairn, Moray, Banff, Stirling, Dumbarton, Ren- 

 frew, Arran, Argyle but occurs in Mull. 



10 C. Balmacarense, W. B. Turner (Desmid. Notes in the 

 "Naturalist," Nov. 1893). "Of medium size, slightly and 

 regularly curved, gently attenuate, ends expanded and 

 rotundo-truncate. Suture not central. Membrane smooth 

 and colourless. Endochrome in indistinct fillets " (eight in 

 number, p. lit), " vesicles scattered." Long., 315-322 p ; lat., 

 20-2 i ,j. ; lat. apic, i6p. (W. B. T.) (Our Plate IV. fig. 6.) 



