586 



the year around: it accompanies C. tripos f. atlantica and reaches its 



maximum at the same time. viz. in the autumn. [See tables.] 



Note. C. macroceras Ehbg. has not been found in the samples; it seems to 

 be rather rare (or wanting?) in the North Atlantic Ocean west of the line drawn 

 between Scotland-Iceland, but is common in the North Sea. 



83. C. longipes (Bail.) Cleve, Fish. Board f. Scotland, 1897, fig. 2; 

 Peridinium longipes Bailey, Smithson. Contrib., 1854, fig. 35; C. tripos, 

 var. tergestina Sehutt,Pflanzenleben, p. 28, lig. 20 IV b and p.70, fig. 35 II. 



Fig. 140. Fig. 141. 



Fig. 140. Ceratium longipes (Bail.), f. oceanica n. f'., a specimen with rather short antapical-horns ('■'■" ,i- 

 Fig. 141. Ceratium longipes (Bail.), a specimen wlth short and widely diverging antapical-horn (approaching 



C. arcticum Ehbg.) ( 1:, "/ t i. 



Of tbis species two forms, analogous to the above-mentioned 

 forms of C. tripos, occur, viz. f. oceanica n. f. and f. baltica n. f. The 

 form oceanica is more robust and has shorter and more spiniferous 



horns, while f. baltica is more slender 

 and almost destitute of spines. The 

 figures by Bailey (1. c.) and Gran 

 (Plankton, 1902, fig. 2) represent f. 

 oceanica, to which my figures (140 and 

 141) also beloiig, but they have unusu- 

 ally short antapical-horns, and one of 

 them approaches C. arcticum Ehbg. 



C. longipes is a boreal, oceanic form, 

 which occurs rather commonly along the 

 Færoes all the year around; it reaches 

 its maximum in the autumn. [See tables.] 



The form baltica belongs to the 

 Baltic and the Ku Uegal and folio ws 

 the waters of the Baltic west and northwards in the Skagerak and 

 along the west coast of Norway. I have given a ligure of it, drawn 

 after a specimen from the Danish waters, and Bergh' s fig. 20 

 (Morphol. Jahrb., 1881) also belongs to it. 



Fig. 142. Ceratium longipes Bail., f. baltica n. f. 

 a specimen from the Western Baltic i ' ■" , 



