STAU14ASTRUM. 173 



Bohm. 1SS8, p. 212; De Toni, Syll. Alg. 1880, p. 1193; West, Alg. N. 

 Wales, 1890, p. 294; Gutw. Flor. Glon. Okolic Lwowa, 1891, p. 66: 

 West, Alg. W. Ireland, 1892, p. 180; Alg. Engl. Lake Distr. 1891', 

 p. 732 ; Liitkem. Desm. Attersees, 1893, p. 567 ; Roy & Biss. Scott. 

 Desm. 1S93, p. 237 ; 1894, t, 4, f. 4 ; Nordst. Index Desm. 1896, p. 109 ; 

 W. \ G. S. West, Welw. Afric. Freshw. Alg. 1897, p. 181 ; Alg. S. 

 England, 1897, p. 494 ; Schmidle, Lappmark Siisswasseralgen, 1898, 

 p. 5S ; Liitkem. Desm. Millstiittersees, 1900, p. 21 (sep.) ; W. & G. S. 

 West, Alga-fl. Yorks. 1901, p. 101 ; Alg. N. Ireland, 1902, p. 51 ; Freshw. 

 Alg. Orkneys and Shetlands, 1905, p. 25 ; Borge, BeitrJige Alg. 

 Schweden, 1906, p. 46 ; Larsen, Ferskvandsalg. Vest-Grim 1. 1907, 

 p. 349 ; W. & G. S. West, Freshw. Alg. Burma, 1907, p. 214. 



Goniocystis (Staurastrum) dilatata Hass. Brit. Freshw. Alg. 1845, p. 353, 

 t. 85, f . 5. 



Phy cast rum dilatatum Kiltz. Phycol. germ. 1845, p. 138. 



Staurastrum dilatatwmva,T. obtusilohum De Not. Desm. Ital. 1867, p. 53, t. 4, 

 f. 47; Nordst. Freshw. Alg. N. Zeal. 1888, p. 41, t. 4, f. 19; West, Alg. 

 W. Ireland, 1892, p. 180; Alg. S. England, 1897, p. 494 ; Lutkem. Desm. 

 Millstattersees, 1 1 JOO, p. 21 (sep.) ; W. & G. S. West, Alga-fl. Yorks. 

 1901, p. 101 ; Alg. N. Ireland, 1902, p. 51 ; Freshw. Alg. Ceylon, 1902, 

 p. 177 ; Freshw. Alg. Orkneys and Shetlands, 1905, p. 25 ; Further 

 Contrilt. Plankton Scott. Lochs, 1905., p. 487; Corn]). Stiidy Plankton 

 Irish Lakes, 1906, p. 86 ; Teodoresco, Mater, flor alg. Rouman. 1907, 

 p. 185 : G. S. West, Alg. Yan Yean, K09, pp. 28, 38 ; W. & G. S. West, 

 Brit. Freshw. Phytoplankton, etc., 1909, p. 182. 



Cells small, about as long as broad or sometimes a 

 little longer, deeply constricted, sinus widely open and 

 minutely acuminate at the extremity ; semicells elliptic- 

 subfusiform, dorsal margin convex, ventral margin 



~ o 



greatly inflated in the median part, so that the greater 

 portion of the semicell is raised up on a smaller ventral 

 piece, lateral angles rounded or rounded-truncate. 

 Vertical view 3-5 (usually 4) -angular, angles of one 

 semicell often alternating with those of the other, sides 

 deeply concave, angles rounded or rounded-truncate. 

 Cell- wall finely granulate, granules arranged in con- 

 centric rings around the angles, and in regular series 

 between the angles, extreme apex smooth or with a 

 few minute punctulations. 



Zvgospore (?) " somewhat barrel-shaped, with round 

 ends, and has numerous raised bands, passing longi- 

 tudinally round it, giving the end view an undulated 

 appearance ' (Roy ' Bissetf). 



Length 21-46 p, ; breadth 22-46 p.; breadth of 

 isthmus 7'5 13 /z ; diam. zygosp. 48 p.. 



ENGLAND. - Cumberland ! Westmoreland, up to 

 2400 ft. on Helvellyn ! (Ralfs). Lancashire ! W., K, 



