]44 BRITISH DESMIDIACE.E. 



t. 28, f. 2 ; Arch, in Priteh. Infus. 1861, p. 748, t. 10, f. 10-14 : Eabenh. 

 Flor. Europ. Ali^ar. Ill, 180S, p. 1.31 ; Kirchn. Al-\ Sclilcs. 1S7S, p. 141 ; 

 Wolle, Desm. U.S. 1SS1, p. 45, t, 7, f. 1(5 ; Cooke, Urit. Desm. 1886, p. 1':?, 

 t. 12, f. 2 ; Hans-;-. Prodr. Al^onfl. Bohm. 1888, p. 182 ; De Toni, Syll. 

 Alt?. 1889, p. 844; Hoy & Biss. Scott. Desm. 1894, p. 244; West & < i. S. 

 West, Now and Int.'Freshw. Al\ 1896, p. 151; Al<?. S. England, 1897, 

 p. 481 ; G. S. West, Alu-a-fl. Cambr. 1S99, p. 112; West & G. S. W.-st. 

 Alga-fl. Yorks. 1900, p. 51 ; Alg. N. Ireland, 1902, p. 23. 

 Arthrodia Ehrenberfjil Kuntze, Eevis. gen. plant. 1891, p. 883. 



Cells large, stout, 4-5-J times longer than their 

 diameter, moderately curved, outer margin 110-120 

 of arc, inner margin concave but inflated in the median 

 part, gradually attenuated to the apices, which are 

 obtusely rounded ; cell-wall smooth and colourless ; 

 chloroplasts with eight to ten ridges, and containing 

 numerous scattered pyrenoids ; terminal vacuole with 

 a cluster of small moving granules. 



Zygospore globose and smooth, with an outer 

 mucous, lamellose coat. 



Distance between apices (length) 382-541 ju, ; breadth 

 72-137 /x ; breadth near apices 12-18 /x, ; diam. zygosp. 

 113-118 p.. 



ENGLAND. Cumberland ! Westmoreland (up to 

 2,400 ft. on Helvellyn)! (R< lifts). W., N., and E. 

 Yorks ! Cheshire (Roy). Leicester (Roy). Essex ! 

 Cambridge! Gloucester (Riilfi). Middlesex! Surrey 

 (zygosp. from Wimbledon Common) ! (Rolfs). Sussex 

 (Bays). Kent! (Ralfs). Hants! (Roy). Devon 

 (Bennett). Cornwall ! (Ralfs). 



WALES. Moel Fammau ! \ Glyder Fawr.(at 2,700 ft.) ! , 

 Pen-y-gwryd (Roy), and Snowdon (at over 3,000 ft.), 

 Carnarvonshire ! 



SCOTLAND. Ross, Inverness, Aberdeen ! , Kincardine, 

 Perth ! , Fife (Roy fy fiissett). Plankton of Loch Boon, 

 Ayr ! Sutherland ! Orkneys ! Shetlands ! 



IRELAND. Creggan Lough, Galway ! Carrantuohill, 

 Kerry ! River Dargle, Wicklow ! Dublin (Archer). 

 Kilkeel, Down ! C lough, Antrim ! 



Geogr. Distribution. France. Belgium. Germany. 

 Austria and Galicia. Bosnia in Hungary. Italy. 

 Portugal. Norway. Sweden. Denmark. N., Central, 



