573 



37. C. constrictum Gran, Protophyta, 1897, p. 17, PI. I, figs. 

 11 — 13, PI. III, lig. 42. 



A boreal-temperate, neritic species which is usually rather rare around 

 the Færoes, found from March t<> August and a few specimens in Oc- 

 tober, l)iit in Mav 1902 predominant. Endocysts found (rarely in Au- 

 gust, September and October. [See tables.] 



Note. To tliis section belong C. Vanheurckii (Iran. and perhaps C. incisor 

 Laud., C. siamense Ost I'.. C. coronatum Gran. 



Sectio 4. Similes. Chains few-celled; Chro matophores two; 

 hoop narrow, not x /3 of the length of the cell; foramina narrow; 

 valves of the cells with a hump; awns straight; endocysts with 

 spines on both valves. 



38. C. simile Cleve, Bih. Sv. Vet. Akad. Handl., Hd. 22, 3, No. 4, 



p.30, lig. 1. 



A boreal species which has only once been found in the plankton 

 in March 1901; but in 1902 not rare in August— September. 



Sectio 5. Stenocinctae. Chromatophore one; hoop narrow, nol 

 73 of the length ol* the cell; foramina rather narrow; terminal awns 

 ihicker than the others, curved and for the most part diverging 

 greatly; endocysts somewhere about the midtlle of the cell, and with 

 numerous spines on both valves. 



39. C. Schuttii Cleve, Bih. Sv. Vet. Akad. Handl., Bd. 20, 3, 

 No. 2, 1884, p. 14, PI. I, lig. 1. 



The type is a temperate, neritic species which belongs to the 

 North Sea and southwards, but a smaller and more slender form, 

 which is in sotne respects intermediate between the type and 

 C. Willei Gran, occurs in the North Atlantic Ocean (cfr. Ostenfeld, 

 Iagttagelser, 1899, pp. 53 — 54), and this form was once observed in 

 plankton from the Færoes (February 1899). 



Note. The following species belong to this section: C. af fine Laud.. C. Ralfsii 

 Cl., C. javanicum CL, C. Willei (Iran. and perhaps C. paradoxum Cl. 



Sectio 6. Laciniosae. Chromatophores one or two; hoop rather 

 large; foramina large; terminal awns mostly thicker than the others, 

 not diverging greatly; endocysts (in C. brevesmå C. laciniosum) smooth 

 on both valves, but nol in the middle of the cell. 



1<>. C. breve Schutt, Ber. Deutsch. bot. Gesellsch., 1895, p. 38, 

 fig. 4 a, b; Ostenfeld, Nyt Magazin Naturv., 1901, p. 295, lig. 6. 



A temperate, neritic species, which has its centre of distribution in 

 the North Sea. Along the Færoes found once only Mav l.S'.IN . 



