KONGL. SV. VET. AKADEMIENS HANDLINGAR. BAND. 22. N:0 8. 79 



depresse semicirculari medio leviter retusis, angulis loborum obtusis, superioribus (et in- 

 ferioribus) loborum lateraliuin sa;pe productis, incisuris inter lobos ovato-ellipticis vel ex- 

 terne magis angustatis; e vertice visas ovales; e latere lineares apicibus late rotundatis. 

 Membrana scrobiculato-punctatse. 



A Didymidio (Eucosmio) Kutzingiano Reinsch Algenf. p. 123, tab. 8, fig. 3 a — c 

 •praecipue differt tumoribus nullis, lobis lateralibus majoribus non obcordatis. 



Long. 140—158 ,u; lat, 90—114 fi; lat. lob. pol. 90—102 t** lat. lob. pol. ad bas. 

 50 — 56 /u- lat. isthm. 24 ,«; crass. 54 — 60 ,«, 



This plant seems to unite Micrasterias with Euastrum. And if the inflated pro- 

 tuberances had not been absent, I should have referred it to the latter genus, but as Mr. 

 Ralfs Brit, Desm. p. 76 remarks, the inflated protuberances are always found in true 

 species of Euastrum. 



Euastrum denticulatum (Kirchn.) Gay /? elongatum nov. var. Tab. 3, fig. 10. 



Paullulo longius, lobo polari cum lobis lateralibus fere confluenti, unde latera semi- 

 cellularum fere recta (granulis acutiusculis 4) evadunt, ceterum ut in forma novizelandica. 



Long. 32—34 ,«; lat. 22 ,«; crass. 13 ,«. 



As the lateral lobes sometimes are more distinctly prominent than in my figure, 

 although not so much as in E. denticulatum forma typica, I think nevertheless that it 

 rnay prove to be a variety of that species, which it in other points much resembles. 



Cosmarium amoenuui Ralfs A' mediolaeve Nordst. 

 Long. 56 ,"; lat. 30 ti; lat, isthm. 15 /u; crass. 22 ,«. 



Cosmarium speciosum Lund. (i australianum nov. var. Tab. 5, fig. 9. 



Fere duplo majus quaru var. simplex, granulis asgre conspicuis, basalibus supra 

 isthmum nullis, isthmo paullo minus lato. Nuclei amylacei? Membrana subtiliter punctata. 



Long. 80—88 ,«; lat, 52—60 ,«; crass. 36—42 ,«; lat, isthm. 20—24 /n. 



The granules are extremly low, those at the lower angles always visible, but the 

 rest only to be seen on a dry empty membrane. In outlines of fronds it often seems 

 much to resemble Cosmarium Cucumis. As to its specific position, I am indeed in some 

 doubt, but for the present I think it best to consider this plant a variety of C. speciosum. 



Cosmarium nasutum Nordst. />' subnasutum (Racib.) Nordst. 



Forma cum spec. e Nova Zelandia prorsus congruens, sed paullulo minor (sed major 

 quam forma polonica) aculeolis marginalibus binis. Long. 34 ,«; lat. 32 ,«; crass. 16 /u. 



Cosmarium triplicatum Wolle Desm. Unit, Stat, p. 73, tab. 19, fig. 3 — 6. 



fi paucius nov. var. Tab. 5, fig. 15. 



Semicellula? saepius sursum paullo angustataj angulis superioribus late rotundatis, 

 rnargine aculeolis robustis brevibus munitis, singulis (rarissime binis) paullo supra angulos 

 inferiores, 2 — 3 (rare 4) distantibus in angulis superioribus, sed ceterum nullis infra mar- 

 ginem; a latere et e vertice visae late ellipticse utroque fine truncata? 2 seriebus aculeorum 

 inter apices. 



