144 



Schutt, F. 



!> )> 

 " 'I 



Wille, N. 

 Zederbauer, E. 



K. OKAMURA. 



1893. Das Pflanzenleben der Hochsee. — Reise- 

 beschreibung der Plankton-Expedition. 



1896. Peridinalcs und Bacillariales. — Engler u. 

 Prantl : Die natürl. Pflanzenfam. Lief. 143- 

 145. 



1900. Centrifugal Dickenwachsthum der Membran. 

 Bot. Ztg., 1900. 



1903. Schizophyceen. — Brandt's Nordisches Plank- 

 ton XX. 



1904. Ceratium hirundinella in den österreichischen 

 Alpenseen. — Osterreich. Bot. Zeitsch. Jahr. 

 1904. No. 4 u. 5. 



Postscript. 



At a time when the printing of the present paper was nearly finished, 

 I have received Schroder's interesting work " Beiträge zur Kenntnis des 

 Phytoplanktons warmer Meere " kindly sent me by the author. In that 

 paper, a number of Ceratium species, mostly from the Pacific, are described 

 as new. I regret to say that I differ from him with regard to the status 

 assigned to several of the species put down by him. It will be admitted 

 by all that the organisms in question are subject to very considerable 

 variation as to their morphological characters. Thus, as I have mentioned 

 in the text, even the two individuals at the ends of one and the same 

 Ceratium chain may differ in the curvature and the direction of antapical 

 horns to such an extent, that when observed singly and separately their 

 specific identity may be placed in doubt (see fig. 1, Pl. III.). Nearly 

 equally striking is the variation shown by C. gibbcrum (figs. 3 a-d) in the 

 curvature of the right antapical horn. The fame may further be said of 

 C. volans (fig. 18, Pl. IV) and of C. horridum (figs. 21 a-f). Taken all in 



