STAUEASTRUM. 133 



Angles with a small mucro or a mamilla. 



11. tit. tu mid-urn. 



12. St. conspicuuni. 



13. St. aver sum. 



14. St. brevispinum. 



15. St. laticeolatum. 

 Angles thickened. 



16. St. pachyrhynchum. 

 Semicells obversely triangular. 



17. St. Clepsydra. 

 Semicells rhoniboidal. 



18. St. imlegam. 



19. St. angulatiun. 

 ft Sinus closed and linear. 



+ Semicells widely subpyramidate-trapeziform or sub- 

 semi-circular. 



20. St. orbiculare. 



21. St. suborbiculare. 



22. tit. retusmn. 

 ij Semicells elongately subpyramidate-inflated. 



23. St. Cosmarioides. 



** Angles distinctly produced into a hollow mamillate lobe. 



24. St. tortum. 



25. tit. subpygmteum. 



26. St. corniculo.tum. 



6. Staurastrum muticum Breb. 

 (PL CXVIII, figs. 16-20.) 



Binatella mutica Breb. Alg Falaise, 1835, p. 57, t. S. 



? Staurastrum trilobum Menegh. Conspect. Alg. Eugan. 1837, p. 18 (sep.). 



St. muticum Breb. in Menegh. Synops. Desni. 1840, p. 228 ; Ealfs, Brit. 

 Desm. 1848, p. 125, t. 21, f. 4, t. 34,1 13 ; Arch, in Pritch. Infus. 1861, 

 p. 740; Rabenh. Flor. Em-op. Alg. Ill, 1868, p. 200; Kirchn. Alg. Schles. 

 p. 163 ; Gay, Monogr. loc. Conj. Montpellier, 1884, p. 64 ; "VVolle, Desm. 

 U. S. 1884, p. 119, t. 39, f. 11, 12 [figures poor"! ; Cooke, Brit. Desm. 1887, 

 p. 156, t. 51, f. 6 ; Hansg. Prodr. Algeiifl. Bohm. 1888, p. 210 ; De Toni, 

 Syll. Alg. 1889, p. 1177 ; West, Alg. N. Wales, 1890, p. 293 ; Heimerl, 

 Desm. alp. 1891, p. 605; West, Alg. W. Ireland, 1892, p. 176; Alg. 

 Engi. Lake Distr. 1892, p. 731 ; Liitkem. Desm. Attersees, 1893, p. 563 ; 

 Roy & Biss. Scott. Desm. 1893, p. 241 (p. 23 sep.) ; Nordst. Index 

 Desm. 1896, p. 179 ; W. & G. S. West, Alg. S. England, 1897, p. 494 ; 

 G. S. West, Variation Desm. 1899, p. 391 ; W. & G. S. West, Alga-fl. 

 Yorks. 1900, p. 100 ; Alg. N. Ireland, 1902, p. 49 ; Freshw. Alg. Ceylon, 

 1902, p. 178 ; Borge, Alg. erst Regnell. Exped., II. Desniid. 1903, p. 106 ; 

 Larsen, Freshw*. Alg. E. Greenland, 1904, p. 98; W. & G. S. West, 

 Freshw. Alg. Orkneys and Shetlands, 1905, p. 25 ; Comp. Study Plank- 

 ton Irish Lakes, 1906, p. 86 ; Borge, Beitrage Alg. Schweclen, 1906, 

 p. 43 ; Larsen, Ferskvaiidsalg. Vest-Gronl. 1907, p. 351 ; G. S. West, 

 Alg. Yan Yean, 1909, pp. 15, 28; W. & G. S. West, Brit. Freshw. 



