10 BRITISH DESMIDIACE.E. 



Length 21-26 pi ; breadth 21-25 (JL ; breadth of isth- 

 mus 6-7 [JL ; length of spines up to 2*5 pi. 



ENGLAND.- -Brother's Water, Westmoreland! En- 

 bridge Lake, Hants (Rot/). 



SCOTLAND. Alford and Tomachar, Aberdeen (Roy & 

 Biss.). 



Geogr. Distribution.- -Finland. Italy. Austria. Aus- 

 tralia. New Zealand. Brazil. Patagonia. 



The more elliptical and inflated form of the semicells and the 

 small spreading spines seem to be characteristic of this variety. 



Var. inflatum West. (PI. CXXX, figs. 3-5.) 



Staurastrum dejectum var. inflatum West, Alg. W. Ireland, 1892, p. 170, t. 22, 

 f. 11 ; West & G. S. West, Alg. N. Ireland, 1902, p. 44 ; Freshw. Alg. 

 Orkneys and Shetlands, 1905, p. 24 ; Borge, Botan. Notis. 1913, p. 27. 



Cells much larger than in the type, semicells more 

 elliptical in form and very inflated, sinus acute, spines 

 at the angles much shorter and directed outwards. 



Length, without spines, 35*5-43 \JL ; breadth, without 

 spines, 33*5-52 ^ ; breadth of isthmus 10*3-12 pi ; length 

 of spines 2*8-4*3 p. 



WALES.- -In the plankton ! 



SCOTLAND.- -Loch Ruar, Sutherland ! Plankton of 

 Loch Mor Bharabhais and Loch Cuthaig, Lewis, Loch 

 Laxadale, Harris, and Loch nan Eun, N. LHst, Outer 

 Hebrides ! Plankton of the Orkneys and Shetlands ! 



IRELAND.- -Derryclare Lough, Ballynahinch, and in 

 the plankton of Lough Corrib, Co. Galway ! Plankton 

 of Lough Neagh and Lough Beg, Londonderry ! 



Geogr. Distribution. Sweden. Norway. 



This large variety is more frequent in plankton than in any 

 other habitat. Borge (' Botan. Notiser.' 1913, p. 27) suggests 

 that it is simply a large form of var. patens Nordst., and certainly 

 it does resemble this variety in the form of its semicells. 



ST. DEJECTUM var. CONVERGENS Wolle, ' Desm. U. S.' 1884, 

 p. 121, t. 40, f. 7, 9-11 ; De Toni, ' Syll. Alg.' 1889, p. 1138; 

 Harris in " Journ. Quek. Micr. Club,' 1920, p. 25. Harris (loc. 



