STAURASTROI. 59 



Alg. 1808, p. 212; Xordst. Xorges Desm. 1873, p. 30; Delp. Desm. 



subalp. 1877, p. 148, t. 11, f. 1-4; Kirchn. Alg. Schles. 1878, p. 170; 



Gay, Monogr. loc. Conj. 1884, p. 68 ; Wolle, Desm. U. 8. 1884, p. 140, 



t. 45, f. 4 ; Cooke, Brit. Desm. 1887, p. 151, t. 52, f. 2 ; Boldt, Desmid. 



Gronland, 1888, p. 36 ; West, Desm. Mass. 1889, p. 5 ; De Toni, Syll. 



Alg. 1889, p. 1167; Anderss. Sverig. Chlor. 1890, p. 12; West, Ate. 



W. Ireland, 1892, p. 175, t. 24, f. 5 ; Alg. Eng. Lake Distr. 1892, 



p. 19 ; Liitkem. Desm. Attersees, 1893, p. 564 ; Roy & Biss. Scott. 



Desm. 1894, p. 26 ; West & G. S. West, Alg. 8. England, 1897, p. 493 ; 



Coniere, Desm. de France, 1901, p. 171. t. 12, f. 17 ; West & G. 8. West, 



Alga-fl. Yorks. 1902, p. 99; Alg. N. Ireland, 1902, p. 48; Schroder, 



GaUertbildung Alg. 1902, p. 163, t, 7, f. 14 : Teodoresco, Mater, flor. 



Alg. Rouman. 1907, p. 184 : West & G. 8. West, Brit. Freshw. Phyto- 



plankton, 1909, p. 175 ; Kaiser, Beitr. Algenfl. Traunstein u. Chiemgau, 



1914, p. 153. 



Didymidium Hystrix B. ma jus Reinsch, Algenfl. Frank. 1867, p. 171. 

 Staurastrum polytrichum var. alpiniim Schmidle, Weit. Beitr. Algenfl. 



Rheineb. u. Schwarzwald, 1895, p. 81, t. 1. f. 20. 

 Xanthidium homceacanthum Schmidt. Grundl. Ateenfl. Liineburg. Heide, 



1903. p. 17. t. 1. f. 4. 



Cells rather under medium size, about l\ times longer 



.1 O 



than broad, deeply constricted, sinus acute and open ; 

 semicells elliptical, with the angles broadly rounded ; 

 cells provided with a number of short stout spines, 

 arranged chiefly at the angles, with a few sparsely 

 scattered on the faces. End view triangular, sides 

 somewhat concave, angles broadly rounded, spines more 

 numerous at the angles and almost wanting in the 

 middle of the lateral margins. Chloroplast axile, with 

 a central pyrenoid in each semicell. and a pair of lobes 

 extending into each angle. 



Zygospore orbicular, provided with a number of long 

 stout spines, forked at the apex. 



Length, without spines, 32-56 JJL : with spines, 40- 

 64 u : breadth, without spines, 27-37 pi ; with spine-. 

 40-45u.; breadth of isthmus 8-1 0[x; diam. zygosp., 

 without spines, 27 '5 pt ; length of spines 15 [i. 



ENGLAND.- -Plankton of Codale Tarn and Easedale 

 Tarn. Cumberland ! Westmoreland and in the plankton 

 of Ennerdale Water ! Lancashire ! W., N., and E. Yorks ! 

 Cheshire (Roy). Berks (Griffiths). Burnham Beeches, 

 Bucks ! Surrey ! Sussex (Ralfs). Hants ! Wilts ! Devon ! 

 (Harris, Bennett). Cornwall ! 



WALES. General ! (At 2200 feet on Glyder Each). 

 In the plankton ! 



