Conjugata}, Detmidiacea^, Staurastrum. 1223 



Sectio 10. Semicellulae e fronte visa! apioibus lateralibus oppositis in proces- 

 sus 1-2 elongatos, hyalinos, plerumquo apice fissos abeuntibus; e vertice 

 visa) angulis processn simplici terminata^, subinde processibus conrormibus 

 ornatse. 



* SemicellulaB e vertice visfc processibus secundariis plus quam 1 in quoque 

 augulo. 



219. Staurastrum eustephanum (Ehrenb.?) Ralfs Brit. Desm. p. 215, 2047 

 Rabenh. Fl. Eur. Algar. III, p. 220, Mask. New Zeal. Desm. p. 

 244, f. 11, Wolle Desm. U. S. p. 147, t. 48, f. 9-11, Cooke Brit. 

 Desm. p. 177, t. 62, f. 2, Besmidium euslephanu7n Ehrenb. Verbr. 

 1843, p. 124, t. 4, f. 23, Siephanoxanthium eusiephanum Kuetz. 

 Species p. 184, Siaurasirum pseudofurcigerum Cooke in Journ. 

 Quek. Micr. Club 1880, VI, p. 210, t. 14, f. 1-3. — Suba;que lon- 

 gum ac latum, granulatum, marginibus plus minus serratis ; semi- 

 cellulis ellipticis, angulis productis, furcatis; e vertice visis trian- 

 gularibus, processibus 9 plerumque inter centrum et raargines in- 

 sertis pra^ditis, siugulis (totaliter 3) in unoquoque angulo, aliis 



6 in superficie superiori extantibus. 



Hah. in stagnis in Britannia (Cooke, Ralfs), Germania (? Ra* 

 benhorst), America boreali (Eiirenberg, Bailey, Wolle), Nova 

 Zelandia (Maskell). — Diam. 50-75 a. (ex Wolle). 



220. Staurastrum xyphidiophorum Wolle Bull. Torrey Bot. Club vol. 2948 

 XII, n. 1, p. 5, tab. XLVII, f. 21, Fresw. Alg. U. S. p. 44, t. 57, 



f. 11-22, t. 60, f. 19. — Parvum, dimidia parte diametro longius, 

 profunde constrictura, sinu angusto, basi rotundato et irregulari- 

 ter arapliato; semicellulis trausverse oblongis. marginibus latera- 

 libus verrucosis; margine terrainali in spinara unilateralera, lia- 

 statara vel in circiter 9 aculeos porrecto; merabrana levi, aliquan-' 

 tulura striata; a vertice visis triangularibus, angulis late trunca- 

 tis pleruraquo trilobis, lobis spina verticali prasditis, lateribus con- 

 cavis. 



Hab. in stagnis pr. « Stillwater et Minneapolis » Americ?e bo- 

 realis (Wolle). — Dimens. 40 et ultra === 25-30. Species, quod ad 

 sectionem, dubia. 



** Semicellnlffi processibus seoundariis in quoque angulo singulis. 



221. Staurastrum verticillatum Archer in Micr. Journ. 1869, p. 196, 2049 

 Cooke Brit. Desm. p. 177, t. 61, f. 3. — Inter species radiatas 

 hucusque in Europa cognitas fere maximarn magnitudinera attingit; 



