97 



DÜBENIA ELEGANS, Nob. 

 (Tab. 3, Fig. 1-7). 



Synon. Virgularia elegans, D. Videnskabsselskabets Forhandlinger i 

 Christiania 1859, p. 251. 



— Stylatula elegans, Richiardi, 1. c. p. 73. 



— Styl elegans, Kölliker, 1. c. P. 225, Fig, 137-138. 



I Videnskabsselskabet i Christiania har den ene af 

 os i 1859 anmeldt en ny Art, nemlig Virgularia elegans, 

 som vi allerede dengang antog kom til at danne en ny 

 Slægt. Da lang Tid er hengaaen siden denne Anmel- 

 delse fandt Sted, har den amerikanske Naturforsker Ver- 

 rill imidlertid opstillet lignende Former fra Kalifornien 

 under Slægtsnavnet Stylatula, hvortil Eichiardi har hen- 

 ført denne vor Søfjær. Men da den i fiere væsentlige 

 Charactermærker afviger fra Stylatula, og dertil fuldkom- 

 men stemmer overens med den af os opstillede Slægt 

 Dubenia, maa den henføres til denne. 



Destoværre ere alle de Exemplarer, vi have fundet, 

 større og mindre Stykker, hvilket hindrer os fra at levere 

 en ganske fuldstændig Beskrivelse; det væsentligste kunne 

 vi dog fremhæve. 



Det største Stykke af den polypbærende Stok, som 

 vi fandt, er 275 Mm. langt, og har endnu paa sin neder- 

 ste Del temmelig store Polyper (Tab. 3, Fig. 1). Paa 

 den øverste Del ragede Axen omtr. 8 Mm. overj Sar- 

 cosomaet. 



Stokken er stiv og paa dens Ventralflade sees en 

 Fure, der her danner Grændsen for de rudimentære Fin- 

 ner (Fig. 4). Disse ere yderst korte og fremkomme 

 egentlig derved, at Polypernel ved deres Grunddel ere 

 sammenvoxede. Paa de to nærmest Ventralsiden stø- 

 dende Polyper iagttages denne Sammenvoxning at strække 

 sig næsten op til en Trediedel af Polypkroppen. De ru- 

 dimentære Finner støttes af en Kalkplade, bestaaende af 

 en vifteformig Samling af Spicier, hvoraf de kortere i 

 Regelen ikke naa op over det Sted, hvor Polyperne ere 

 sammenvoxede, medens de længste rage med deres Spid- 

 ser frit op over Finnen (Fig. 3 a). Finnerne sidde lidt 

 afvexlende, danne kun korte Mellemrum, der baade paa 

 Dorsal- og Ventralfladen ere nøgne. Paa begge disse 

 Flader findes henimod Finnerne en temmelig ophøiet 

 Vulst, der svarer til de radiære Kanaler og bidrager paa 

 Ventralfladen til at gjøre Furen paa de Steder dybere 

 (Fig. 4). Ved Siden af Finnerne, næsten omfattende 

 disse, findes paa Stokken flere Rækker 5 — 6 Zooider (Fig. 

 4, 5), der snart paa Dorsalfladen samle sig i en Gruppe, 

 just paa det Sted, hvor den ene Polyprække støder hen- 

 imod den anden (Fig. 3 b, 5 b) snart lige over Finnerne 

 noget nærmere Ventralfladen (Fig. 4). Polyperne, der ere 

 5 — 6 i Antal, have et cylindrisk, meget langstrakt Legeme, 

 ere 3 — 4 Mm. lange i rolig Tilstand; men naar de ud- 

 strække sig, opnaa de en Længde af 6 — 7 Mm. (Fig. 4 

 og 5). Tentaklerne ere 2 Mm. lange, temmelig tykke, 

 forsynede med mange tykke Traade (Pinnulæ) og en 

 Række stærke Spicier, der gaa lige ud til Spidsen (Fig. 

 6 — 7). Ingen Celle findes, dette sees bedst paa de to i 

 Gruppen yderst stillede Polyper; thi hos dem er hele den 



DÜBENIA ELEGANS, Nob. 



(Tab. 3, fig. 1—7). 



Synon. Virgularia elegans, D. Videnskabsselskabets Forhandlinger 

 i Christiania 1&59, p. 251. 



— Stylatula elegans, Richiardi, 1. c. p. 73. 



— Styl elegans, Kölliker, I.e. p. 225, fig. 137—138. 



In the scientific society in Christiania, one of us in 

 1859 announced a new species, Virgularia elegans, which 

 we even at that time presumed would form a new genus. 

 A long time has elapsed since the announcement took 

 place; and the American naturalist Verrill has presented 

 similar forms from California under the generic name 

 Stylatula, to which Richiardi has referred this our sea- 

 pen; but as it differs in several essential characteristics 

 from the Stylatula, and at the same time entirely coin- 

 cides with the genus Dübenia established by us, it must 

 be referred to the latter. 



Unfortunately all the specimens we have found are 

 only larger or smaller fragments, for which reason we 

 cannot communicate a very complete description. We 

 can however elucidate the most essential points. 



The largest piece of the polypiferous trunk which 

 we found is 275 Mm. long, and had still on its lower 

 part rather large polyps (see tab. 3, fig. 1). On the upper 

 part, the axis projected about 8 Mm. beyond the sar- 

 cosoma. 



The polyp ary is stiff; and on its ventral side there 

 appears a furrow which here forms the boundary for 

 the rudimentary fins (fig. 4). The fins are extremely short, 

 and are produced by the polyps being connate at their 

 basal part. In the two polyps in contact nearest to the 

 ventral side, this connexion appears to extend to nearly 

 one third part of the body of the polyp. The rudimen- 

 tary fins are supported by a calcareous plate composed 

 of a fan-like collection of spicula, of which the shorter 

 ones do not usually extend beyond that part where the 

 polyps are connate ; while the longest project with their 

 points free beyond the fin (üg. 3 a). The fins are situ- 

 ated somewhat alternately, forming only short intervals 

 which both on the dorsal and ventral surfaces are bare. 

 On both these surfaces there exists, towards the fins, a 

 distinct protuberance, which corresponds to the radial 

 canals, and contributes on the ventral surface to make 

 the furrow at those places deeper (fig. 4). At the side 

 of the fins and nearly surrounding them, there are on 

 the trunk several (5 — 6) rows of zooids (fig. 4, 5) which 

 are sometimes collected in a group on the dorsal surface 

 just at the spot where one row of polyps meets the other 

 (fig. 3 b, 5 b) and sometimes just over the fins a little 

 nearer to the ventral surface (fig. 4). The polyps, 5 — 6 

 in number, have a cylindrical very elongated body, are 

 3—4 Mm. long when quiescent, but when they extend 

 themselves, they attain a length of 6 — 7 Mm. (fig. 4 and 5). 

 The tentacles are 2 Mm. long, rather thick, furnished 

 with numerous thick filaments (pinnulæ) and a row of 

 strong spicula extending right up to the point (fig. 6 — 7). 

 There are no cells. This is best seen in the two exterior 



