Dansk Botanisk Arkiv, Bd. 2, Nr. 4. 



I. Schizophyceae. 



Lyngbya aestuarii (Mert.) Liebman, Krøyers Tidskr., København 

 1841, p. 492. Probably only accidental^ in the plankton. 



Richelia intracellularis Johs. Schmidt, Vid. Medd. Naturh. For- 

 ening, København, 1901, p. 146, fig. 2. 



To judge from the numerous drawings this interesting endophyte 

 must be very common in the plankton of the Boeton Strait. It 

 always occurred in Rhizosolenia styliformis and related species. 



Trichodesmium Thiebautii Gomont, Journ. de Botanique, 1890, 4, 

 p. 356; Ann. Se. nat. VII e sér., 16, Botanique 1892, p. 197, tab. VI, 

 figs. 2-4. 



Both drawn by Dr. Justesen and found by me in the sample. 



II. Silicoflagellata. 



Dictyocha fibula Ehbg. var. stapedia (Haeck.) Lemmermann, 

 Ber. d. Deutsch, bot. Ges., 19, 1901, p. 261. 

 Found very rarely in the sample. 



III. Peridiniales. 



Amphisolenia bidentata B. Schroeder, Mitteil. zool. Stat. Neapel, 

 li, 1900, p. 20, fig. 16. 



P. T. Cleve (1901, p. 13) records A. palmata Stein from the 

 Malay Archipelago (and not A. bidentata), but it is probably the 

 same species as that to which I have given Schroeder's name. 

 The question is if the two names are synonymous or not; but until 

 Stein's form has been found again, we can not come to a decision 

 in the matter. As far as can be judged from the drawings, the two 

 forms seem to differ in the shape of the posterior part of the 

 hypotheca. — 



With regard to the difficult genus Ceratium I follow E. Jørgensen's 

 excellent monograph l ), which I quote under each species. 



Ceratium breve (Ostf. et Schmidt) B. Schröder, Viertel] ahrschr. 

 d. naturf. Ges. Zürich, 51, 1906, p. 358; Jørgensen, 1. c, p. 40, fig. 84; 

 C. tripos v. brevis Ostenfeld og Schmidt, Vid. Medd. Naturh. For. 

 København, 1901, p. 164, fig. 13. 



I have identified several drawings with this form. Besides the 

 main species the var. parallelum (Schmidt, Bot. Tids., 24, 1901, 

 p. 213, fig. 1) Jørgensen, 1. c, p. 41, fig. 86, was also present. 



C. candelabrum (Ehbg.) Stein, Organ, d. Infusionsthiere, III, 2., 

 1883, tab. XV, figs. 15-16; Jørgensen, 1. c, p. 16, fig. 21. 



Rare; a single drawing. 



') E.Jørgensen: Die Ceratien. Eine kurze Monographie der Gattung Ceratium 

 Schrank. Leipzig 1911 (\V. Klinkhardt). 



