COSMAELUM. 31 



Var. mediolaeve Nordst. (PI. Oil, figs. 5, 6.) 



C. amaenum var. mediolxve Nordst. in Botan. Notis. 1887, p. 100 ; Freshw. 

 Alg. N. Zeal. 1888, p. 50, t. 5, f. 12 ; De Toni, Syll. Alg. 1889, p. 989 ; 

 West, Alg. W. Ireland, 1892, p. 156 ; Eoy & Biss Scott. Desm. 1894, 

 p. 42 ; Borge, Sussw.-Chlor. Feuerland ti. Is. Desola. 1906, p. 26 ; G. S. 

 West, Alg. Yan Yean, 1909, p. 64. 



Semicells destitute of granules in the median part 

 (or lower median part), with two horizontal series of 

 granules across the base, and with the rest of the 

 granules disposed in decussating oblique series. 



Length 45-76 /x ; breadth 26-40 //, ; breadth of 

 isthmus 9-20 /x. 



SCOTLAND.- -Dalbrake in Strachan, Kincardine (Roy 

 $ Bissetfy. 



IRELAND.- -Ballyiiahinch, Galway ! 



Geogr. Distribution.- -Australia. Xew Zealand. 

 Patagonia. 



This variety varies much in size, the largest specimens 

 exceeding those of any other form of C. amncnum. The 

 granules are smaller than in typical C. (inm-Hitm, and their 

 disposition is quite different. The clear space in the median 

 part of each semicell is often punctate. 



238. Cosmarium pseudamoenum Wille. 

 (PI. Oil, figs. 7-9.) 



Cosmarium pseudamcenum Wille, Sydamerik. Algfl. 18S4, p. 18, t. 1, f. 37 ; 



De Toni, Syll. Alg. 1889, p. 996 ; West, Alg. W. Ireland, 1892, p. 156 ; 



Borge, Siissw. Chlor. Archang. 1894, p. 19 ; Liitkem. Desm. Central 



China, 1900, p. 119; W. & G. S. West, Alga-fl. Yorks. 1900, p. 89; Alg. 



N. Ireland, 1902, p. 38 ; Borge, Alg. erst. Regiiell. Exped., II. Desmid. 



1903, p. 85 ; Beitrage Alg. Schweden, 1906, p. 29 ; G. S. West, Alg. 



Third Tanganyika Expedit. 1907, p. 123 [forms]. 

 C. iiiornatum Josh. Burmese Desm. 1886, p. 648, t. 24, f . 26, 27 ; De Toni, 



Syll. Alg. 1889, p. 966. 



Ursinella pseudamcena Kuntze, Revis. gen. plant. 1891, p. 925. 

 U. inornata Kvintze, 1. c. p. 925. 

 Dysphinctium pseudamcenutn Schmidle, Beitr. Algenfl. Schwarzwald. u. 



Rheineb. 1893, p. 92, t. 4, f. 4, 5. [Schmidle's figures are possibly 



C. amoenum ?] 



Cells somewhat small, about twice as long as broad, 

 almost cylindrical, only slightly constricted, sinus a 

 small and open notch ; semicells oblong with the sides 

 straight or very slightly convex, apex broadly rounded 



