567 



SOLENIEAE. 

 VII. CORETHRON Castr., 1886. 



15. C. criophilum Castr., Challenger Rep., p. 85, PI. 21, ligs. 12, 

 14, 15; C. hystrix Hensen, 1. c, PI. 5, lig. 49: Ostenfeld, Iagttagelser 

 1900, p. 52; Cleve, Fifteenth Ann. Report of the Fishery Board for 

 Scotland, 1897, p. 298, lig. 15. 



OccurS rarely and singly in the plankton, generally in Jury No- 

 vember. An oceanic plankton -form. found in most of the temperate 

 parts of the oceans. 



VIII. LAUDERIA Cleve, 1873. 



1(5. L. borealis Gran, Bemerk., 1900, p. 110, PI. IX, ligs. 5—9; 



Ostenfeld, Iagttagelser 1900, p. 53; L. annulata Cleve, pro parte. 



Only found in a single sample from Klaksvig in 1897 Augusl A 

 temperate, neritic plankton-form which follows the west-coast of Europe 

 from the English Channe! and the Haltit- northwards lo northern Norway. 



IX. LEPTOCYLINDRUS Cleve, 1881). 



17. L. danicus Cleve, Kanonbaaden Hauch's Togter, Kjøben- 



havn, p. 54 (1889). 



A neritic species widely distributed, found along the west-coast of 

 Europe in the Mediterranean, the Red Sea, the Malaj' Arehipelago and 

 the Gulf of Siam. [See tahles. 



Its occurrence around the Færoes in the years of 1897 — 1902 

 is rather curious. In 1897 it was common in a sample from Thors- 

 havn, gathered in July, and in 1898 predominant in all the samples 

 gathered during May and June in different localities (it was in faet 

 the predominant species of the whole area in those two months), 

 but in 1898 — 1902 it was only found occasionally in a few speci- 

 mens and never occurred as a common or predominant species. 

 Such an irregular occurrence is the case with several plankton-dia- 

 toms; they predominate in some years, but are absent (or almost 

 so) in others. 



X. DACTYLIOSOLEX Castr.. 188G. 



18. D. antarcticus Castr., Challenger Rep., p. 75, PI. 9, lig. 7. 



A temperate, oceanic form, only found once along the Færoes 

 November). It occurs every year in the North Atlantic Ocean, bul 

 rather sparingly. 



