105 



dels 2, dels 4 Polyper, der som oftest ere sammenvoxede 

 ved Granden og antage derved el fingerformet Udseende, 

 Fig. 15. 16. Fra Stammen udspringe stundom en enkelt, 

 stundom 2 Polyper. men hyppigere mindre Polypgrupper, 

 bestaaende af 3 — 6 Polyper, som forene sig i en kort, 

 temmelig tynd Stilk, Fig. 15. Stammen. Grenene og 

 Smaagrenene ere rige paa Spilder. 



Polyperne ere cylindriske, retraktile, 10 — 12""" lange, 

 temmelig klare med en 5""" lang Forkrop og 3""" lang 

 Bagkrop, Fig. 17. Hele Kroppen er inkrusteret af Spikler, 

 der paa Bagkroppen ligge paatvers, men paa Forkroppen 

 paalangs, hvor de danne stærkt fremspringende Ribber, 

 som gaa over paa Tentaklerne, der ere omtrent 4'""' lange 

 og forsynede med Pinnuler, som ligeledes ere rige paa 

 Spilder, Fig. 18. Munden danner en Tverspalte; Mund- 

 skiven næsten flad. Naar Polypen trækker sig ind, dan- 

 ner Bagkroppen dens Celle, der sees da som en halvrund 

 Forhøining over Stammens eller Grenens Niveau, Fig. 16, a. 



Anatom isk-histologiske Undersøgelser. 



Stammen og Grenene ere udvendigt beklædte med et 

 Ectoderm, der bestaar af flere Lag store, polyædriske 

 Celler med en stor, aflang Kjerne og et rundt Kjerne- 

 legeine, Fig. 19, a; imellem disse Cellers inderste Lag 

 iagttages aflange, encellede Slimkjertler. Indenfor Ecto- 

 dermet er et bredt, hyalint Bindevævslag, Fig. 19, 6, der 

 sender sine Forlængelser indad. og som. idet de anastomo- 

 sere med hverandre, danne Skillevægge for Kanalerne. 

 Fig. 20, «. Saavel det ydre Bindevævslag som Skille- 

 væggene ere ualmindelig rige paa store Ernæringskanaler, 

 beklædte og tildels ganske udfyldte af noget langstrakte 

 Epitheleeller, Fig. 19, c. 20, b. Paa Bindevævets indre 

 Flade, ligesom paa Skillevæggene, ligger som sædvanligt 

 Muskellaget forsynet med cilierende Endothel. I Ecto- 

 dermets dybere Lag, i Bindevævet og dets Forlængelser, 

 der danne Skillevæggene (det egentlige Coenenchym), tindes 

 Spikelafleiringer. I Ectodermet ligge Spiklerne tæt paa 

 hverandre, omsluttede af Ectodermceller, og i selve Binde- 

 vævet, hvor Spiklerne ligge mere enkeltvis, ere de lige- 

 ledes omgivne af Ectodermceller, Fig. 19. d; dette sees 

 kun. efterat Stammen eller Grenen er afkalket, og fine 

 Tversnit ere udpræparerede og farvede. Det hele Coenen- 

 chym viser sig da at være forsynet med Spikler, Fig. 20. c. 



Den norske Nordhavsexpedition. I). C. Danielssen: Alcyonida. 



(Pl. XV. figs. 14. 15. K5). The lowest third part of the 

 stem is most frequently bare. with the exception that 

 occasionally one or a couple of polyps rna v be seen 

 there. From the branches there proceed, parti v. a few 

 polyps, partly branchlets placed very close to each other; 

 these branchlets are short. but thick, and carry, sometimes 

 2. and sometimes 4, polyps which, most frequently, are 

 concreted together at the base. and thus acquire a digital 

 appearance (Pl. XV, iigs. 15. 16). From the stem there 

 proceed, occasionally, a single, sometimes two polyps, but 

 more frequently small groups of polyps, consisting of 

 3 — 6 polyps which unite together into a short, pretty thin 

 stalk (Pl. XV. fig. 15). The stem, the branches, and 

 the branchlets are rieh in spicules. 



The polyps are cylindrical, retractile, and measure 

 10 — 12'"'" in length; and they are rather pellucid. They 

 have an anterior body b'" m in length, and a posterior body 

 3""" in length (Pl. XV, fig. 17). The entire body is en- 

 crusted with spicules which, on the posterior body, are 

 placed transversally. but on the anterior body longitudi- 

 nally, where they form strongly protuberant ribs which 

 pass over to the tentacles; these latter measure about 

 4" m in length, and are furnished with pinnules which are 

 also rich in spicules (Pl. XV, fig. 18). The oral aper- 

 ture forms a transversal fissure, and the oral disk is 

 almost flat. "When the polyps retract themselves, the 

 posterior body forms the cell for them. and they then 

 appear as a convex projection beyond the surface of the 

 stem or brauch (Pl. XV, fig. 16, a). 



Anatomo-histological Examination. 



The stem and the branches are, exteriorly, clad with 

 an ectoderm, consisting of several lavers of large poly- 

 hedrical cells containing a large oblong nucleus, and a 

 globular nucleus body (Pl. XV, fig. 19, a). Between the 

 innermost layers of these cells, there are observed oblong 

 unicellular mucous glands. Inside the ectoderm. there 

 is a broad hyaline connective-tissue laver (Pl. XV, 

 fig. 19, 6) which sends its prolongations inwards, and 

 which, whilst they anastomoze with each other, form the 

 divisional walls of the ducts (Pl. XV, fig. 20, a). Both, 

 the exterior connective-tissue layer as wel! as the divisional 

 walls, have the usual wealth of large nutritory ducts ; these 

 are clad, and in some cases quite stuffed, with somewhat 

 elongated epithelial cells (Pl. XV, fig. 19, c. 20, b). On 

 the inner surface of the connective-tissue, as well as, also. 

 upon the divisional walls, is placed, as usual, the muscu- 

 lar layer, which is furnished with ciliating endothelium. 

 In the deeper layers of the ectoderm. in the connective- 

 tissue, and also in its prolongations forming the divisional 

 walls (the sarcosoma proper), spicular deposits are found. 

 In the ectoderm, the spicules are situated close to each 

 other enclosed by the ectoderm cells, and in the connec- 

 tive-tissue itself, where the spicules are found more 



14 



