KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAN 



d 25. n:o 5. 103 



processubus) tiificlis vel quadritidis: merabrana punctata. Magis minus quam f. typica, 

 paullo X. armato (i basidentato Nordst. (N. Z. Alg. p. 42, t. IV, f. 21) consimile. 



Long. 104, lat. 80, lat, isth. 34, long. proc. 8 /u. Taf. XIII, f. 4. 



This, like Xordstedt s New Zealand form is much smaller than the type, it dif- 

 fers from the latter in having 2 apical processes & 4 placed around and ecjuidistant 

 from the scrobieulus. 



Khasia, super Brahmaputra tlumen. ex. Utricularia sp., comm. G. von L. 



The sub-genera of this genus, Holaeanthum and Schizacanthum, proposed by 

 Lundell, Desm. Suec. pp. 74 — 5, 1871, are admirable, but they do not meet the 

 requirements of eertain forms which have been eonsidered as aculeate Cosmaria'. I 

 hold with Ralfs that no aculeate form is a true Cosmarium, hence I would add ano- 

 other sub-genus, the sub-genera standing thus: 



A. Schizacanthum, Lind., 1. c. 



Typ. sp. X. armatum. 



B. Holacauthum, Lund., 1. c. 



Typ. sp. X. cristatum, fascieulatum, acanthophorum. 



C. Micracanthum, n. s. g. juixpog, parvus; (txuv&u, spina). Cellula? cum vel sine tumöre 

 centrali; spinis vel aculeis parvis, non elongatis, munitae. 



Typ. sj). X. cosmariforme, nob.; X. (Cos.) armatum Josh. ex. p. f. 24, 25. 

 Burm. Desm.; X. torquatum, nob. 



I would not include under this sub-genus such a form as Cos. ovale Ralfs, as in 

 that the projectious are only dentate, not aculeate or spinous; yet the distinction 

 between a tooth" and one of the shorter, spines' is somewhat difficult. The ventral 

 projection in this genus is frequentlv absent, and when it does not appear its absence 

 tends to confuse the observer. 



[As inöst of this little memoir was written long ago, I have been asked, »Do the 

 suggestions of Boedt (Desm. Grönl. p. 31 separ. 1888), conflict with vour views?» 

 To this I reply, that Dr Boldts sub-genera are founded solely upon the character, 

 and distribution in the cell, of the ehlorophyll — and that, as I have elected to sketch 

 an outline of a classificatioii (partly experimental) based on exteriör form alone, our 

 views do not conflict in any wa} r . Of course, sec. Lundell, I should place that char- 

 ming species X. Gramlandicum, Boldt 1. c, from its form, under SeJtizacaniltum, as 

 the processes thereon appear to be something more than what its author styles verrucce^] 



Gen. 19. Stau rastrum, Meten, 1828. 



(In Nova Acta vol. XIV, Pt. II, p. 777, 1829; Desmidinm, Ehr. Inf. ex. p. [et Pentasterias]; Mengh. Synops. 

 p. 224 (excl. Arthrodesmus Ehr.); Phyeastrum, Ki ta. Phyc. Genu. p, 137; Goniocystis, (Trigonoc;/sti$, Stan- 

 rastrum et Pentasterias) Hassall, Br. Fr. Alg', p. 349; Phyeastrum, Asteroxanthium et JStephanoxanthium, Kltz 

 Sp. Alg. 1849; Phyeastrum, (Amblyactinium, Pachyactinium et Stenactinium) NÄG. Einz. Alg. 1849 ; iStaurastrum, 

 Ralfs Br. Desm. (char. emend.) p. 1J9, 1848; Didymidium sub. gen. Staurastrum Reinsch, Alg. Frank. p. 150, 



18G7; Didymodadon Ralfs Br. Desm. p. 144, includ.). 



1. S. sniaragdinum, n. sp. S. minus, fere tam longum quam latum, late ovale; semi- 



cellulae late semicirculares, angulis basalibus et dorso rotundatis; membrana dense 



