STAURASTRUM. 33 



Flor. Europ. Alg. 1868, p. 205 ; Lund. Desm. Suec. 1871, p. 62, t. 4, f . 2 ; 

 Kirchn. Alg. Schles. 1878, p. 169 ; Cooke, Brit. Desm. 1887, p. 163, t. 57, 

 f. 3 ; Hansg. Prodr. Algenfl. Bohm. 1888, p. 212 ; De Toni, Syll. Alg. 

 1889, p. 1198 ; Roy & Biss. Scott. Desm. 1893, p. 17 ; Liitkem. Desm. 

 Central China, 1900, p. 123 ; West & G. S. West, Freshw. Chlorophy. 

 Koh Chang. 1901, p. 92 ; Freshw. Alg. Ceylon, 1902, p. 176 ; Freshw. 

 Alg. Burma, 1907, p. 212, t. 16, f. 7. 

 Phycastrum (Stenactinium) bifidum Nag. Gatt. einz. Alg. 1849, p. 128. 



Cells rather under medium size, about as lono' as 



7 O 



broad, not counting the spines; constriction fairly deep, 

 sinus subrectangular ; semicells subelliptical or subtri- 

 angular, dorsal margin slightly convex, ventral margin 

 very tumid, provided at each angle with two stout 

 spines, which usually lie in the same horizontal plane 

 and project obliquely downwards ; cell- wall smooth. 

 Vertical view triangular, sides straight or slightly con- 

 cave, angles broad and bifid, lobes separated by a broad 

 concavity, and each one tipped with a sharp spine. 



Zygospore unknown. 



Length 28-33 \L ; breadth, without spines, 29-33 JJL ; 

 with spines, 48-56(1 ; breadth of isthmus 11 "5-1 4 JJL. 



ENGLAND. Cornwall (Marquand) . 



SCOTLAND.- -Poole we, Eoss (Roy & Biss.). 



(reoyr. Distribution.- -France. Germany. Hungary. 

 Italy. Sweden. Finland. Poland. N. Russia. Central 



/ 



China. Japan. India. Ceylon. Burma. Siam. Java. 



63. Staurastrum longispinum (Bail.) Arch. 

 (PL CXXXIV, fig. 1.) 



Didymocladon / longispinum Bail. Microscop. Observ. 1851, p. 36, t. 1, f. 17. 

 Staurastrum longispinum Arch, in Pritch. Inf. 1861, p. 743 ; Rabenh. Flor. 



Europ. Alg. 1868, p. 221 ; Wood, Freshw. Alg. N. Amer. 1874, p. 148 ; 



Wolle, Desm. U.S. p. 145, t. 41, f. 7 ; Lagerh. Bidr. Amerik. Desm.-fl. 



1885, p. 249, t. 27, f. 28 ; De Toni, Syll. Alg. 1889, p. 1199 ; West, Alg. 



W. Ireland, 1892, p. 180 ; West & G. S. West", Alg. N. Ireland, 1902, p. 45 ; 



Scott. Freshw. Plankton, I, 1903, p. 545 ; Brit. Freshw. Phytoplankton, 



1909, p. 174. 

 St. (Schizastrum) longispinum Turn. Freshw. Alg. E. - India, 1893, p. 132, 



t. 23, f. 12. 



Cells very large, deeply constricted, sinus acute, 

 opening widely ; semicells subelliptical or subtriangular, 

 dorsal margin slightly convex, ventral margin more 



VOL. v. 3 



