575 



As in other piaces il lins ;ilso here two tnaxima, viz, in the 

 spring und in the autumn. It predominates in the samples taken 

 at the end of March to the beginning af May, and again in the 

 end of August to the beginning of November. Optimum of tempe- 

 rature is in spring about 5° — 7° C.« and in autumn about 8°— 9°C. 

 Curiously enough no endocysts have been mel with around the 

 Færoes. 



Note. C. tortissimum Gran seems l<> belong to tliis section. 



Sectio 9. Compressae. Chromatophores numerous, small; cells 

 compressed; intercalary awns, thickened and twisted, occur inler- 

 mixed with the thin normal ones; endocysts (in C. contortum) 

 smooth. 



4."). C. contortum Schutt, Ber. Deutsch. hot. Gesellsch., 1895, 

 p. 44; Gran, Protophyta, p. 14, PL II, lig. 32. 



A boreal-temperate, oeritic form, which is generally rather rare around 

 the Færoes, but in July 1901) predominant rarelv with endocysts, and 

 also in September 1902). Found in March— May, July— September; op- 

 timum of temperature about 10° C. [See tables.J 



Note. G. compressum Laud. (incl. C. Keller i Brun) and C. subcompressum 

 Schroder belong to this section. 



Sectio 10. Furcellatae. Chromatophore one: terminal awns not 

 differentiated ; endocysts occurring excentrically in the inother-cells, 

 and lying closely together, two and two, hearing thick coalesced 

 awns; valves of the endocysts smooth or with short spines. 



46. C. cinctum Gran, Protophyta, 1897, p. 24, PI. II, figs. 23—27. 

 A boreal, neritic species which is characteristic of the plankton of 



leeland; along the Færoes only found in a few specimens three times 

 in July— September. 



47. C. scolopendra Cleve, Bih. Sv. Vet. Akad., Bd. 22, 3, No. 4, 

 p. 30, fig. 4; Ostenfeld, Nyt Magazin Naturv. Kristiania, 1901, 

 p. 295, fig. 7. 



A temperate, neritie species found only once along the Færoes (Octo- 

 ber 1900, a single chain). 



Note. C. furcellatum Bail. belongs to this section, and perhaps C. Paulsenii 

 Ostf. from the Caspian Sea. 



Sectio 11. Sociales. Chains curved, emhedded in mucilage, 

 forming irregularly spherical colonies; chromatophore one: endo- 

 cysts smooth or with small spines. 



48. C. sociale Lauder, Transact. Microsc. Soc. London XII, 

 1864, p. 77, PI. VIII, lig. 1. 



