COSMAE1UM. 223 



distinctive form, but its granulation is very variable. 

 Scarcely two individuals can be found with precisely the 

 same disposition of granules, and in all cases the granulation 

 is somewhat indistinct. Much confusion has existed concern- 

 ing the different forms frequently met with, and Schmidle 

 was the first to point out the close affinity of certain so-called 

 "species" which he afterwards grouped under C. liumile. 



We find C. liumile mostly in large ditches, and at the 

 weedy margins of large ponds and lakes. It occurs very 

 rarely among* submerged Sphagnum, but is frequent in the 

 plankton of certain of the British lakes. 



Var. striatum (Bolclt) Sclimidle. (PI. LXXXV, figs. 



21, 22.) 



Cosmarium striatum Bolclt, Siber. Chlorophy. 1885, p. 104, t. 5, f. 9; Desm. 



Gronland, 1888, p. 14 ; De Toni, Syll. Alg. 1889, p. 940 ; Anderss. Sverig. 



Chlor. 1890, p. 15 ; West, Alg. N. Wales, 1890, p. 289 ; Liitkem. Desm. 



Attersees, 1893, p. 553 ; Roy & Biss. Scott. Desm. 1894, p. 175 ; Nordst. 



Index Desni. 1896, p. 241 ; West & G. S. West, Desm. Singapore, 1897, 



p. 164 ; Him, Desm. Filmland, 1903, p. 13 ; Larsen, Fresliw. Alg. E. 



Greenland, 1904, p. 89. 



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

 Cosmarium liumile (Gay) Nqrdst. var. striatum (Bolclt) Schmidle, Beitr. 



alp. Alg. 1895, p. 389 ; West & G. S. West, Alga-fl. Yorks. 1900, p. 77 ; 



Borge, Beitriige Alg. Schweden, 1906, p. 34. 



Cells without granules, apical angles of semicells not 

 emarginate, with no granule in the centre of the semi- 

 cells. 



Length 12*5-1 6/1; breadth 12-1 7 //,; breadth of 

 isthmus 4-5 {JL ; thickness 6-12 p.. 



ENGLAND.- -Pilmoor, X. Yorks ! Delamere, Cheshire 

 (Roij). Enbridge Lake, Hants (Eon). New Forest, 

 Hants ! 



WALES.- -Glyder Fawr, Carnarvonshire (Ron). Lljn 

 Cor on, Anglesey ! 



o / 



SCOTLAND. Aberdeen and Kincardine (Eoy $ 

 Bissett). 



Geoc/r. Distiibution.--GermQ.iij. Austria. Galicia in 

 Austria (var.). Norway. Sweden. Finland. Faeroes. 

 Siberia. Singapore. United States. Patagonia. 



This variety is distinguished by its rounded apical angles 

 and by the complete absence of granules. The apex is undu- 

 late exactly as in the type. 



