119 



lindes lidet Coenenchym, der dog har Spilder. Stammen. 

 Grenene og deres Coenenchym rigt paa Spilder. Svælget 

 forsynet med Spilder. 



Artskarakter. 



Zoanthodemet indtil 25""" hoit. Basaldelen membran- 

 agtigt udvidet. Stammen fast, furet, nøgen i større Stræk- 

 ninger. Grenene yderst faa, 3 — 1, korte, endende i en 

 tyk Klump, rigt besat med Polyper. Disse ere langstrakte, 

 cylindriske, staa tæt sammen og forsynede med 8 Længde- 

 ribber, imellom hvilke 8 nedsænkede Felter. Tentaklerne, 

 omtrent halvt saa lange som Kroppen, have Spikelbeklæd- 

 ning paa lade deres abdrale Flade. Pinnulerne spikelholdige. 

 Polypcellen halvrund. otteribbet og spikelrig. Svælget har 

 4 Dobbeltrækker Spilder. Paa Basaldelen almindeligst ellip- 

 tiske, takkede Spindler, Dobbeltstjerner og Druespikler. 

 Pa;i Stammen hyppigst sammensatte Stjerner. Dobbelt- 

 stjerner. Spindler og Druespikler. Paa Grenene takkede 

 Koller. Paa Polypkroppen lige og krummede, takkede 

 Spindler og takkede Valser. Svælg- og Coenenchymspiklerne 

 væsentlig takkede Spindler. 



Nidalia arctica, n. sp. 



Tab. XXI, Fig.,29— 66. Tab. XXII, Fig. 67—83. 



Zoanthodemet indtil 35""" hoit. Basaldelen membra- 

 nos, rørformigt udvidet. dannende en større eller mindre 

 Hulhed, udfyldt med en mørk Lermasse, Fig. 29, a. 



Stammen, omtrent 25" 



hoi og 6" 



bred ved ( ) verga ngen Ira 



fra Basaldelen, er i en Strækning af 1U""" nøgen, rund, 

 lidt furet paalangs, Fig. 29. b. men udvider sig nu til en 

 Bredde af il)""", Fig. 29, c, imedens den mod Toppen 

 smalner lidt af. Det er denne udvidede Del af Stammen. 

 der bærer Polyperne, og som. naar disse ere lidt sammen- 

 faldne, antage Formen af en Strobilus. 



Polypcellerne staa tæt sammen, ere temmelig vide, 

 runde, med 8 stærke Ribber, der aftage noget i Styrke, 

 idet de gaa over paa Polypens Bagkrop og ere adskilte ved 

 ligesaa mange spikelløse Furer, Fig. 30, b. 



betweenthem, little sarcosoma can be observed; it, however, 

 contains spicules. The stem. the branches and their sarco- 

 soma, rich in spicules. The gullet furnished with spicules. 



Specific charaeteristies. 



The Xoanthodem measures up to 25""" in height. The 

 basal part is membranaceously dilated. The stem hard, 

 grooved, and bare over a considerable extent. The branches 

 extremely few in number (3 — 4 short ones), terminate in a 

 thick clump richly beset with polyps. These are elongato- 

 cylindrical, placed closely together. and are furnished with 

 8 longitudinal ribs. between which there are 8 depressed 

 areas. The tentacles about half the lengtli of the body, and 

 furnished with a spicular sheathing on their aboral surface. 

 The pinnules contain spicules. The polyp-cell semi-circular, 

 eight-ribbed, and contains spicules abundantly. The gullet 

 has four double series of spicules. In the basal part, elliptic, 

 spicate fusees, bistellates, and racemiform spicules are the 

 most frequent. In the stem, complex stellates, bistellates, 

 fusees, and racemate spicules are. most usually, observed. 

 On the branches, spicate subclavates. On the polyp-body, 

 straight, aud curved, spicate fusees, and spicate cylinders. 

 The gullet and sarcosoma spicules are principally spicate 

 fusees. 



Nidalia arctica, n. sp. 



Pl. XXI, figs. 29— <>(>. Pl. XXII, figs. 67—83. 



The Zoanthodém measures up to 35""" in heigtø 

 The basal pa.rt is membranaceous, tubularly dilated. and 

 forms a larger or smaller cavity filled with a dark- 

 coloured aluminous substauce (Pl. XXI. fig. 29, a). The 

 stem measures about 25""" in height, and 6"™ in breadth at 

 the .transition from the basal part. Through an extent of 



10 the stem is bare; it is cylindrical. slightly grooved 



longitudinally (Pl. XXI. fig. 29, b), bnt then becomes dilated 



to a breadth of lo (Pl. XXI, fig. 29, c), whilst, towards 



the summit it diminishes in thickness a little. It is upon 

 this dilated part of the stem that the polyps occur, and 

 when the polyps are a little retracted they acquire the 

 form of a Strobil. 



The polyp-cells are placed closely together, and are 

 pretty wide; they are cylindrical. and have 8 strong ribs 

 which diminish in strength. somewhat, as they pass over 

 to the posterior body of the polyp, and they are separated 

 from each other by an equal number of spicule-free grooves 

 (Pl. XXI. Hg. 30, b.) 



