COSMAR1UM. 15 



striction not quite so deep. The granules are disposed in 

 fairly regular transverse and vertical series, and the cell-wall 

 between the granules is quite smooth. The vertical view is 

 elliptical with no flattening of the sides. 



The var. latuin (= C. latum Breb.) and other forms with 

 more rounded semicells are much more frequent than the 

 somewhat angular Desmid described by Balfs. although for 

 the most part these forms have been recorded under the name 

 " C. conspersum." 



Borge ('Clilor. Norska Finmark.' 1892, p. 9) has recorded 

 a "forma minor" of this species from the extreme north of 

 Norway with a length of only 52 fi and a breadth of 44 ^. 



Var. latum (Breb.) nob. (PL XCIX, figs. 5, 6.) 



Cosmarium latum Breb. Liste Desm. 1856, p. 128, t. 1, f. 10; Kabeiili. 



Flor. Em-op. Alg-. Ill, 1868, p. 158 ; ? Cooke, Brit. Desm. 1887, p. 101, 



t. 41, f . 8 ; De Toni, Syll. Alg. 1889, p. 999 ; West, Alg. N. Yorks, 1889, 



p. 292; Eoy & Biss. Scott, Desm. 1894, p. 105, t. 2, f. 10; Nordst. Index 



Desm. 189(3, p. 156 ; W. & G. S. West, Alg. S. England, 1897, p. 488 ; 



Some Desm. U. S. 1898, p. 306 ; Alga-fl. Yorks. 1900, p. 88 ; Borg. 



Freshw. Alg. Faeroes, 1901, p. 227 ; Borge, Siisswasseralgen Siid. 



Patagon. 1901, p. 21 ; W. & G. S. West, Alg. N. Ireland, 1902, p. 37 ; 



Borge, Beitrage Alg. Schweden, 1906, p. 30 ; W. & G. S. West, Freshw. 



Alg. Burma, 1907, p. 206. 

 C. anomalum Delp. Desm. subalp. 1877, p. 29, t. 9, f. 10-12, and 15 



[figures poor and inaccurate]. 

 Ursinella lata Kvintze, Eevis. gen. plant. 1891, p. 925. 



Cells proportionately wider; semicells generally with 

 a conspicuous upward dilation, so that tlie apical part 

 is distinctly wider than the basal part, apex usually 

 (but not always) more convex ; granules about equal 

 in size and number to those of typical C. conspersum, 

 arranged in vertical and indistinct oblique series. 



Length 88-107/*; breadth 76-88^; breadth of 

 isthmus 27*5-34 /x; thickness 40-50 p. 



ENGLAND.- -Near Bowness, Westmoreland! (Bissett). 

 Mickle and Great Shunnor Fells, Pilmoor, and Carlton 

 Bank, N. Yorks ! Delamere, Cheshire (Roy). Brent 

 Eeservoir, Middlesex ! 



WALES.- -Capel Curig !, Llyii Ogwen !, and Glyder 

 Fawr (Roy), Carnarvonshire. 



SCOTLAND.- -Sutherland !, Eoss, Inverness, Aberdeen, 

 Kincardine, Forfar, Perth!, Stirling (Roy $ Bissett). 

 Lewis and Harris, Outer Hebrides ! 



