20 



VeffetatioHstid. Sommer. 



ForeJxomst. Marsteiien juni 95 (Hjort), vestkysten 

 juni 96 (S. MMer), Bergensfjorden juni— august 95 {Nord- 

 gaard). 



Udhredelse. Nordsøen. 



Fra CIi. Scliiitfii adskilles denne art ved de svagt 

 divergerende terminalhorn, den lange baandcylinder og de 

 smalere foramina. 



14. Chætoceros diadema. (Ehr.) Gran mscr. 



Tab. uostr. II, tig. 16— is. 

 Syn. Syndendrium diadema, Ehr. (1854) T. 3.'), A. XVIII, 13. 



— — , Bail. (185G) T. I, fig. 24, 2.5. 



— — , Brightw. (1850) T. VII, fig. 49—52. ' 

 Chætoceros sp. bidet. Scliiitt (1888) T. III, fig. VI. 



— paradoxnm, Cl. var. subsecimda, Grun. in Van Heurck 



Synops. T. 82 bis, fig. 6. 



— — var. Liidersii, Engl. (1883) p. XI. 



— — Schiitt (1895) p. 37. 



— Clevei, Schiitt (1895) p. 40, fig. 8 o, 6. 



— grænlandicwn, Cl. (1896, 4) p, 7, T. II, fig. 3—5. 

 .— cwvisetum. Cl. (1894) pro parte (?) (1896, 5) p. 29, 



fig. 12. 



Kjederne rette, undertiden svagt snoede, bredde 11 — 

 46 ;i<. Cellerne i frontstilling rektangulære med afrundede 

 hjørner, skallerne svagt konvek.^io. foramina udtrukket af- 

 lange, svagt og jevnt indsnørede mod midten. Baandets 

 høide variabel, mindst 1/4 af cellelrengden (?). 



Kromatofor 1, pladeformet. frontstillet. 



Hornene rette, iidgaar lidt indenfor skallernes hjørner 

 i skråa retning, krydses lidt udi-nfor udgangspunkterne i 

 høide med cellens ydre raud eller lidt udenfor denne, hoier 

 derefter skarpt af. to i sagittal. to i transversal retning, 

 de sidste til hver sin side af sagittalplanet. 



Terminalhornene noget fortykkede paa midten, spids- 

 vinklet divergei^ende. 



Sporerne noget ensidig i raodercellerne, med sekun- 

 dærskallen vendt mod modercellens nærmeste skal. Skal- 

 lerne i de smale kjeder hoit Inieforniig hvælvede. i de 

 l)redere næsten flade. mere eller mindre tydehg puklede 

 paa midten. Primærskallen. som ofte er lidt sterkere hvæl- 

 vet, bærer 4 — 12 rette, dikotomisk forgrenede horn, der i 

 almindelighed naar lige til modercellens skal og stanses i 

 sin vækst af denne. Hornenes grene danner stumpe vinkler 

 med hverandre. 



Yegetaiiondid,. Hele aaret. ved vore kyster især vin- 

 ter og vaar. Sporer i marts — juni. 



Forekomst. Vestkysten og Cliristianiafjorden november 

 93 (Hjort), Marstenen juni 95 (Hjoti). Stavanger — Bei-gen 

 februar 96 (Nordgaard), Drøbak februar — marts 96! Lofo- 

 ten marts — april 96 (Nordgaard). Atlanterhavet mai 96 

 (Bie), vestkysten juni 96 (S. Midler), Bergenstjorden juni 

 juli 96 {Nordgaard). 



Feriod of Yegetation. Summer. 



Occurrence. Marstenen, June 1895 (Hjort); W.coast 

 of Norway, June 1896 (S. Midler); Bergen Fjord, June 

 to Aug. 1896 (Nordgaard). 



Distrihidion. North Sea. 



This species is distinguished from Ch. SchiUtii l)y 

 the slightly divergent terminal setæ, the long hoopcylinder, 

 and the narrower foramina. 



14. Chætoceros diadema, (Ehr.) Gran mscr. 



Pl. ir, figs. 16—18. 

 Syn. SyndeHdrium diadema, Ehr. (1854) Pl. 35, A. XVIII, 13. 



— — , Bail. (1856) Pl. I, figs. 21, 25. 



— — . Brightw. (1856) Pl. VII, figs. 49—52. 

 Chætoceros sp. indet. Schutt (1888) Pl. III, fig. VI. 



— paradoxum Cl. var. subsecunda, Grun. in Van Heurck 



Synops. Pl. b2 bis. fig. 6. 



— — var. lAidersii, Engl, (18S3) p. XI. 



— — Schiitt (1895) p. 37. 



— Cln-ei, Schutt (1895) p. 40, fig. 8 a, h. 



— grænlandicum, Cl. (1896, 4) p. 7, Pl. II, figs. 3 — 5. 



— cwvisetum, Cl. 0B^4) pro parte (?) (1896, 5) p. 20, 



fig. 12. 



Filaraents straight, sometiraes slightly twisted, 11 — 

 46 (( wide. Celis. in a front view, rectangular with rounded 

 angles, valves slightly eonvex. foramina elongated oblong, 

 slightly and evenly constricted towards the middle. Height 

 of iioop, variable, at least ^/4 of the length of the cell (1). 



Chromatophore. 1. lamelliform, in front. 



Setæ straigiit. issuing a little within the angles of the 

 valves in an ol)lique direction, crossing a little l)eyond 

 their insertion on a level with, or a little beyond the outer 

 margin of the cell. then turning sharply off. two in a 

 sagittal. two in a transverse direction. tlie latter to oppo- 

 site sides of the sagittal plane. 



Terminal setæ rather thickened in the middle, diver- 

 ging at an acute angle. 



Spores somewhat at oue side in the parent cells, with 

 the secondary valve turned towards the nearest valve of 

 the parent cell. Valves in the narrow lilaments very ar- 

 cuate. in tlie broader ones almost Hat. witli a more or 

 less distinct hump in the middle. Primary valve, which 

 is ofteu a little more vaultod, carries from 4 to 12 straight, 

 dichotoraously ramified setæ, generally reaching as far as the 

 valve of the parent cell, which arrests their further growth. 

 The rami of the setæ form obtuse angles with one another. 



Feriod of Yegetation. The whole year, on our (Norw.) 

 coasts especially winter and spring. Spores from March 

 to June. 



Occurrence. W.coast of Norway and Christiania Fjord, 

 Nov. 1893 (Hjort); Marstenen, June 1895 (Hjort); Stav- 

 anger to Bergen. Feb. 1896 (Nordgaard); Drøbak, Feb. 

 and March 1896; Lofoten. ]March and April 1896 (Nord- 

 gaard); Atlantic Ocean. May 1896 (Bie); W.coast of Nor- 

 way, June 1896 {S. Miiller); Bergen Fjord, June and July 

 1896 (Nordgaard). 



