— 234 — 



Of Flagellates Dinobryon divergens Imh. is common in the 

 sample; it occur with resting spores of the typical form (see the 

 fig. 6). Further Peridinium Willei Huitf.-Kaas and Ceratium hirun- 

 dinella (0. F. Müll.) Schrank have been found in rather few speci- 

 mens. The Ceratium is slender (about 165/,« long) and 4-horned 1 ) 

 as shown in fig. 7. 



The Chlorophyceae are of unusual importance owing to the great 

 quantity of a Conferva, which I have identified with the form 

 described by Prof. Wille in the large work on the plankton of the 

 Danish lakes by G. Wesenb erg-Lund 2 ) under the name Tribo- 

 nema {Conferva) bombycinum (Ag.) Derb. & Sol., forma depauperata 

 Wille. The threads are about 4 — 5/^ thick, very slightly constricted 

 at the cross-walls; chromatophores few (2—4) in number; the 

 microchemical reactions of the cell-walls and cell-contents agree 

 well with those mentioned in K. Bohlin's studies on Confervales 3 ). 

 Professor Wille takes the form quoted as a depauperated T. bom- 

 bycinum, but remarks that if the chromatophores do not exceed the 

 number of four, it must be nearer to T. minus (Wille) Hazen 4 ). 

 As I have seen always 2—4 chromatophores and not more, and 

 I have also through the kindness of Dr. Wesenberg-Lund seen the 

 form from Denmark, I think it better to place it under T. minus 

 as f. depauperata. As suggested by Wesenberg-Lund (1. c. 

 p. 101) I think that the Conferva belongs to the bottom flora and 

 has been broken off from stones etc. by the waves; then it is able 

 to float and perhaps also to grow for some time. 



The other green algae in the plankton are few and occur 

 only in single specimens. I have found Botryococcus Braunii Kütz., 

 Eudorina elegans Ehrbg. 5 ), Oocystis lacustris Ghodat (?), 0. Naegelii 

 A. Br., Staurastrum paradoxum Meyen, var. longipes Nordst., forma, 



x ) Gfr. e. g. Le m m ermann, Plöner Forschungsber. XI. 1904, and Das 

 Plankton Schwedischer Gewässer, Arkiv f. Botanik, Bd. 2. 1904. 



Entz, Geza: A Balaton tudomånyos tanulmånyozåsanak eredményei. II. 

 1. Budapest. 1903. 



2 ) Wesenberg-Lund, G.: Studier over de danske Søers Plankton. Specielle 

 Del. København 1904. p. 100. 



3 ) Boh lin, K.: Studier öfver nâgra slägten af algruppen Confervales Borzi. Bih, 

 Sv. Vet. Akad. Handl., Bd. 23. III. Nr. 3. 1897. 



4 ) Hazen, T.E.: The Ulothricaceae and Ghaetophoraceae of the United States. 

 Mem. Torr. Bot. Glub. XI. 2. 1902. p. 185. 



5 ) In some specimens I have found a parasite which is nearly allied to 

 Rhisophlyctis palmèllacearum Schröder, Ber. Deutsch. Bot. Gesellsch., 1899, 

 Pl.X. f.5. 



