168 BBITISH DESMIDIACE.E. 



St. Sebaldi var. Cooke, in Grevillea, 1881, p. 92, t. 139, f. 5. 

 St. Sebaldi var. Cookeii Gutw. Wahr. d. Prioritat, 1890, p. 72 ; Flor. Glon. 

 Okolic Lwowa, 1891, p. 69. 



Cells relatively more slender than in the type ; pro- 

 cesses much longer and more graceful, nearly parallel ; 

 semicells often with a group of verrucse near the sinus 

 at the base of each process. 



Length 50-81 [x ; breadth, including the processes, 

 88-1 32 fx ; breadth of isthmus 15-22[A. 



ENGLAND.- -Pilmoor, N. Yorks ! 



WALES. Capel Curig ! (Cooke & Wills] and Llyn-y- 

 cwm-fTynon, Carnarvonshire ! In the plankton ! 



SCOTLAND. Falls of Kogie, Eoss ; Brimmond, Slew- 

 drum, Aboyne, Powlair, near Dinnett, Tomacher, Aber- 

 deen ; Cammie, Kincardine ; Dirdie Moor, Perth (Roy 

 & Biss.). New Galloway, Kirkcudbright ! 



IRELAND. Mayo ! Galway, and in the plankton ! 

 Plankton of Lough Neagh ! 



Geogr. Distribution, Germany. Norway. Sweden. 

 Finland. Australia. New Zealand. 



St. Sebaldi var. ornatum is very similar in many ways to St. 

 Manfetdtii Delp. Its processes are, however, longer and more 

 graceful, and its granulation somewhat stronger. 



Var. productum W. & G. S. West. (PI. CXLIX, 



fig. 17.) 



St. Sebaldi var. productum West & G. S. West, Further Contrib. Plankton 

 Scott. Lochs, 1905, p. 504, t. 7, f. 24 ; Compar. Study Plankton Irish 

 Lakes, 1906, p. 86. 



Apex of semicell very slightly convex and quite 

 smooth, except for a series of about 6 emarginate verrucse 

 just within the margin ; angles produced to form long 

 verrucose processes ; vertical view triangular, sides 

 nearly straight and smooth, with a series of emarginate 

 verrucae within each lateral margin ; angles produced 

 into long verrucose processes. 



Length 83 ^ ; breadth, including processes, 108-115 (jt; 

 breadth of isthmus 20 x. 



