79 



væsentlige Characterer større eller mindre Betydning, Af 

 de i Tidernes Løb opstillede Slægter: Zoanthus, Palythoa, 

 Mammillifera, Sidisia, Corticifera, Epizoanthus, har Milne- 

 Edwards kun godkjendt to, nemlig Zoanthus, som udbre- 

 der sig med rodformige Stoloner, og Palythoa, hvis Ud- 

 bredning er i Form af en Plade eller et Teppe. Gosse 

 er imidlertid ikke bleven staaende ved disse to Slægter, 

 men har reduceret dem til én, nemlig Zoanthus, Cuv., 

 idet han ikke har kunnet erkjende, at Befæstningsmaaden 

 egner sig til deraf at danne Slægter. Han har paavist, at 

 hos Slægten Zoanthus forekommer de f or skj elligste Maader, 

 paa hvilke Dyret befæster sig, uden at noget andet Cha- 

 ractermærke, der skulde kunne begrunde en ny Slægt, 

 har været at opdage. 



Foruden de ved den norske Kyst tidligere fundne 

 Arter af Zoanthus, nemlig Zoanthus (Mammillifera) incru- 

 status, Diib. & Kor. og Z. arcticus, Sars, have vi fundet 

 en tredie, som nu skal beskrives. 



ZOANTHUS NOBVEG1CUS, Nob. 



(Tab. 9, Fig. 5, 6). 



Fra den fælles Grund (Cænosark) hæver Polyperne 

 sig i en snart perpendiculær, snart horizontal, snart 

 skjev Stilling (Fig. 5). Polyperne ere kølleformige med en 

 smalere Basaldel, der er cylinderformig. Den øverste Del 

 er henved dobbelt saa stor i Omkreds, som Basaldelen, 

 og ganske afrundet, naar Tentaklerne ere indtrukne. 

 Kroppen har en graagul, tynd, men fast Overhud, hvori 

 fin Sand er incrusteret, og indenfor denne Epidermis er 

 den egentlige Hud bleg, rosenfarvet, spillende lidt i det 

 gule. Munden er aflang, lidt conisk fremstaaende og om- 

 given af en mørkere, rosenfarvet Bing, hvorfra fine, hvide 

 Striber gaa straaleformigt hen til de indre Tentakler. 

 Skiven er, naar den er fuldkommen udslaaet, plan, forsynet 

 paa dens ydre, frie Rand med bladformige Lapper, hvori 

 ligeledes fin Sand er incrusteret, og hvis Antal svarer til 

 den ydre Tentakelrække. Tentaklerne sidde afvexlende i 

 to Rader; men naar Polypen er fuldkommen udstrakt, og 

 Skiven med Tentaklerne fuldstændigt udslaaede, ser det 

 ud, som om der kun var én Rad Tentakler. Hos det fuld- 

 voxne Dyr er der 18 Tentakler i hver Række. 



I den ydre Række ere Tentaklerne omtr. 7 Mm. lange, 

 i den indre ere de noget længere. Størrelsen af Polyperne 

 variere temmelig meget; de største, vi observerede, vare 

 25 Min. høie, 5 Mm. brede ved Basaldelen og 8 Mm. ved 

 Skiven. Paa yngre Exemplarer var Antallet af Tentak- 

 lerne 15 i hver Række, enkelte havde 16. 



Zoanthus norvegicus sidder dels enkeltvis, dels flere 

 sammen; men hyppigst i store Grupper, der kunne ind- 

 tage en knyttet Haands Omfang, og hvori mere end halv- 

 hundrede Polyper ere fæstede ved det fælles Cænosark, 

 der beklæder snart Svampe, saasom Tethea cranium, snart 

 Skaller af Lima excavata og stundom Stammer af Primnoa 

 lepadifera og Paragorgia arborea. 



mode of attachment or other less essential characteristics. 

 Of the genera established in the course of time: Zoan- 

 thus, Palythoa, Mammillifera, Sidisia, Corticifera, Epizo- 

 anthus, Milne-Edwards has only acknowledged two, namely 

 Zoanthus, which expands itself with root-shaped Stolons, 

 and Palythoa, the expansion of which is in the form of 

 a plate or a carpet. Gosse has however not stopped at 

 these two genera, but has reduced them to one, namely 

 Zoanthus, Cuvier; as he has not been able to admit that 

 the mode of attachment is appropriate to the formation 

 of genera. He has shewn that the genus Zoanthus ex- 

 hibits the most different modes in which the animal at- 

 taches itself, without any other characteristic mark by 

 which a new genus might be established, being disco- 

 verable. 



Besides the species of Zoanthus previously found on 

 the Norwegian coast, namely Zoanthus (Mammillifera) in- 

 crustatus Diib. & Kor. and Z, arcticus Sars, we have found 

 a third, which shall now be described. 



ZOANTHUS NOBVEGICUS, Nob. 

 (Tab. 9, fig. 5, 6). 



From the common base (Coenosark) the polyps rise 

 in a sometimes perpendicular, sometimes horisontal, some- 

 times slanting position (fig. 5). The polyps are club- 

 shaped, with a smaller basal part which is cylindrical. 

 The upper part is about double as large in circumference 

 as the basal part and quite rounded when the tentacles 

 are retracted. The body has a greyish yellow, thin, but 

 firm epidermis, wherein fine sand is incrusted; and inside 

 of this epidermis the proper skin is pale rose-colored, 

 with a tinge of yellow. The mouth is oblong, projecting 

 a little conically, and surrounded by a darker rose-colored 

 ring, from which fine white stripes go radially to the 

 interior tentacles. The disc is, when completely expanded, 

 plane, and has on its exterior free margin leaf-like lobes, 

 in which likewise fine sand is incrusted, and the number 

 of which corresponds to that of the outer row of ten- 

 tacles. The tentacles are situated alternately in two 

 rows; but when the polyp is completely extended, and 

 the disc with the tentacles entirely expanded, it seems 

 as if there was only one row of tentacles. In the adult 

 animal there are 18 tentacles in each row. 



In the exterior row, the tentacles are about 7 Mm. long; 

 in the interior they are somewhat longer. The size of 

 the polyps varies considerably: the largest we observed 

 were 25 Mm. high, 5 Mm. broad at the basal part, and 

 8 Mm. at the disc. In younger specimens, the number 

 of tentacles in each row was 15; some had 16. 



Zoanthus norvegicus exists partly single, partly several 

 together, but frequently in large groups that may occupy 

 as much space as a closed hand wherein more than 50 

 polyps are attached by the common coenosark, which 

 may cover sometimes sponges, (Tethea cranium) some- 

 times shells of Lima excavata, and now and then stems 

 of Primnoa lepadifera and Paragorgia arborea. 



