137 



ud af. sit Rør, formodentlig for at søge Føde, og da maatte 

 Alcyoniden spadsere med, alt eftersom Røret blev draget 

 henover Karrets Bund, uden at den paa nogen Maade 

 syntes at generes deraf; thi Polyperne vedbleve at være 

 fuldt udstrakte. Det falder ellers ikke i denne Dyreforms 

 Lod at kunne bevæge sig fra Sted til Sted ; men Organidus 

 Nordenskjoldi synes at høre til de faa Lykkelige. 



Af den givne Beskrivelse viser det sig, at Organidus 

 Nordenskjoldi ikke alene maa danne en ny Slægt, men at 

 den ikke godt kan henføres til nogen af de Underfamilier, 

 hvoraf den store Alcyonidefamilie bestaar. Den synes at 

 nærme sig no get Underfamilien Tubiporinæ ved de lange, 

 i Knipper sammenvoxede Polypceller, men den adskiller sig 

 næsten i alle andre Henseender fra den ; saa dertil kan den 

 ikke henføres, men maa grunde en ny Underfamilie, Organinæ. 



Underfamilie Organinæ. 



Zoanthodemet fattigt paa Coenenchym. Polypcellerne 

 lange, sammenvoxede til en Stamme. 



Slægtskarakter. 



Zoanthodemets Stamme dannes af de sammenvoxede 

 Polypceller. Disse ere lange, cylindriske, bløde, kalkholdige, 

 havende Basaldelen til Bund. Polyperne retraktile; baade 

 Polypkrop og Tentakler vel forsynede med Spikier. Svælget 

 kalkholdig! Kjønnene adskilte. 



Artskar akter. 



Zoanthodemet indtil 20'""' høit. Stammen lige tyk 

 overalt, omtrent 25""" i Omfang. Basaldelen tynd, mem- 

 branagtig, men kun lidet udvidet. Stammen indkneben paa 

 Midten. Polypcellerne, sammenvoxede ved deres indre Væg 

 i hele deres Længde, ere meget lange, gjennemsigtige, cylin- 

 driske, bløde og forsynede med Spilder, der ordne sig i 

 Rækker. En stor Del af Polypcellerne indtage Stammens 

 hele Længde; andre naa kun halvt op paa Stammen, hvor- 

 ved denne faar Udseende af at have Afsatser. Polyperne 

 med Tentaklerne 10 — 12""" lange, kontraktile, cylindriske, 

 men noget udvidede, hvor de gaa over i Cellen, glatte og 

 fuldstændigt gjennemsigtige. Polypkroppen forsynet med 8 

 adskilte Længderibber, dannede af Kalkspikler ;• imellem 

 Ribberne en bred, nøgen Fure, der opimod Tentakelskiven 

 udvides til trekantede Felter, hvis Midtparti indtages af en 

 Pyramide af Spikier. De nøgne Partier, Mundskiven og 

 Tentaklernes adorale Side, rige paa Nematocyster. Tentak- 

 lernes aborale Side og Pinnulerne rige paa Spilder. Ved 



Den norske Nordhavsexpedition. D. C. Danielssen: Alcyonida. 



expiry of some time, the annelid commenced to creep a 

 little distance out of its tube, probably in search of nourish- 

 ment and, then, the alcyonoid was compelled to accompany 

 it accordingly as the tube was drawn along the bottom 

 of the glass vessel without it appearing to be in any way 

 inconvenienced thereby as the polyps continued to be fully 

 extended. R does not, generally, pertain to the lot in life 

 of this animal species to be capable of migrating from place 

 to place, but Organidus Nordenskjoldi appears to belong to 

 the few fortunate ones. 



From the description given, it is evident that not 

 only must Organidus Nordenskjoldi form a new genus, but 

 that it cannot well be assigned to any of the sub-sections of 

 which the large family of Alcyonoids consists. R appears 

 to be related, somewhat, to the sub-section Tubiporinæ, from 

 its long, in bunches, concreted polyp-cells, but it distin- 

 guishes itself in almost all other respects from that sub- 

 section so that it cannot be assigned to it but must serve 

 as the type of a new sub- section, Organinæ. 



The Sub-section Organinæ. 



The Zoanthodem poor in sarcosoma. The polyp-cells 

 long, concreted together into a stem. 



Generic characteristics. 



The stem of the Zoanthodem is formed of the con- 

 creted polyp-ceUs. These are long, cylindrical, soft, calcar- 

 eous, and the basal part of the stem serves as their bottom. 

 The polyps retractile; both, polyp-body and tentacles well 

 supplied with spicules. The gullet calcareous. The sexes 

 separated. 



Specific characteristics. 



The Zoanthodem measures up to 20""" in height. The 

 stem is uniform in thickness throughout, and measures about 

 25 mm in circumference. The basal part, thin, membrana- 

 ceous, and only slightly dilated. The stem constricted at the 

 middle. The polyp-cells concreted together along the entire 

 length of their inner wall; are very long, transparent, 

 cylindrical, soft, and furnished with spicules arranged 

 in series. A large number of the polyp-cells occupy the 

 whole length of the stem ; others extend only half way up 

 the stem imparting to it thus, the appearance of being ter- 

 raced. The polyps with their tentacles measure 10 — 12""" 

 in length, contractile, cylindrical, but somewhat dilated at 

 the point where they pass over into the cell, smooth and 

 quite transparent. The polyp-body furnished with 8 separ- 

 ated longitudinal ribs formed of calcareous spicules ; between 

 the ribs, a broad bare groove which in proximity of the 

 tentacular disk becomes dilated, forming triangular areas 

 whose middle portion is occupied by a pyramid of spicules. 



18 



