574 



41. C. laciniosum Schutt, Ber. Deutsch. bol. Gesellsch. , 1895, 



p. 38, lig. 5 a — c. 



A boreal, ncritic species which is rare around the Færoes, only 

 found in a few specimens in samples from April, July, August, Septem- 

 ber, November; with endocysts but rarely in September 1902. 



42. C. pelagicum Cleve, Arctic Sea, 1873, p. 11, PI. I, lig. 4; 

 C. Ostenfeldii Cleve, Kgl. Vet. Akad. Handl., Bd. 34, No. 1, 1900, p. 21, 

 PI. VIII, Hg. 19; C. laciniosum, aff. Ostenfeld, Iagttagelser, 1899, p. 53. 



In the North Atlantic Ocean an association of plankton-orga- 

 nisms occurs in the spring, in which two small species of Chaeto- 

 ceras are predominant, viz. C. Schiittii, aff. (see No. 36) and C. Osten- 

 feldii (=■ C. laciniosum, aff.). Samples containing this association were 

 found as early as 1868 by Th. Fries, and Cleve published his notes 

 on the examination of these samples in his paper on »Diatoms from 

 the Arctic Sea«, 1873, in which paper he records a new species C. pela- 

 gicum, found at Lat. 60° 25', Long. 19° 50', which is without doubt 

 identical with C. Ostenfeldii: the figure is not well drawn, but the 

 directions of the awns and the large foramina, together with the 

 locality, leave no doubt as to its being identical with the latter 

 species and consequently the older name has the claim of priority. 

 The other species from this association is named »C. Wighamu by 

 Cleve; it is C. Schiittii, aff., not C. Wighami of Brigthwell. 



C. pelagicum occurs only three times in the plankton from the Færoes, 

 viz.: March 1901, June 1900, and August 1902, and in a few specimens. 

 Note. C. disians Cl. belongs to this section. 



Sectio 7. Diademae. Chromatophore one; the primary valve 

 of the endocysts with dichotomously divided processes. 



43. C. diadema (Ehbg.) Gran, Protophyta, 1897, p. 20, PI. II, 

 ligs. 16—18. 



A boreal -arctic, neritic species which is rare around the Færoes; 

 found sparingly in March— May, single specimens in May, July, August, 

 October. [See tables.] 



Note. C. mitra (Bail.) Cleve belongs to this section, and C. dicladia Castr. 

 and C. Lorenzianum Gran are allied to it. 



Sectio 8. Tortae. Chains Iwisted; chromatophore one; awns 

 thin, curved; endocysts (in C. debile) with two short, thick spines 

 on the primary valve. 



44. C. debile Cleve, Bih. Sv. Vel. Akad., Bd. 20, 3, No. 2, 1894, 



p. 13, PI. I, tig. 2. 



A boreal, neritic species, which is eommon around the Færoes. See 

 lables]. 



