153 



se fører lige ind i Rectum. Spiserørets indre Plade er 

 foldet etter Længden, og Folderne ere forholdsvis meget 

 luede. Tab. XVIII, Fig. 6 a; idet Spiserøret gaar over 

 i Tarmen, blive Folderne smalere, men et Stykke bag i 

 Tarmen rage de mere frem og antage oæsten Bladformen, 

 Tab. XVIII. Fig. 6 b, imedens de i den bagerste Del, 

 Rectum, blive overordentlig smale, staa tættere sammen 

 og ere i en langt rigere Mængde tilstede. Tab. XVIII, 

 Pig. 6 c. 



Legemets Overtræk er dannet af en seig Slimmasse, 

 hvori sees indleiret paa den ydre Flade spredte Sandkorn, 

 imedens den indre Flade er glat og uden organisk For- 

 bindelse med Kropshuden. Denne har et temmelig tykt 

 Eetoderm, bestaaende af et Lag hoie, smale, cilierende 

 Cylinderceller med Kjerne og Kjernelegeme, Tab. XVIII, 

 Fig. 8 a. Imellem Cellerne og tildels dækket af dem sees 

 kolbelbrmede, encellede Slimkjertler, Tab. XVIII, Fig 8 b. 

 samt en Mængde Nematocyster, Tab. XVIII, Fig. 8 c. 

 Disse sidste ere især rigeligt tilstede paa Tentaklerne og 

 Mundskiven. Indenfor Ectodermet er et fibrillært Binde- 

 vævslag, Tab. XVIII. Fig. 8 cl, der er rigt paa Bindevans- 

 legemer med Udlobere, samt Ernæringskanaler. Henimod 

 den indre Flade af dette Bindeyæv tindes et temmelig smalt 

 Belte af Cirkulærmuskler, som synes at ligge i Bundter, 

 men ere ikke meget udviklede. Tab. XVIII, Fig. 8 e. Paa 

 Bindevævets indre Flade er fæstet Længde- og Tvermuskler, 

 Tab. XVIII, Fig. 8 f. der ere beklædte med Cylinderepi- 

 thel, Tab. XVIII, Fig. 8 g. 



Der er 12 Septa, som tåge deres Begyndelse fra 

 Kroppens indre Veg og strække sig lige fra Analaabningen 

 og op til Mundskivens Underflade, hvortil de fæste sig. 

 ligesom de alle inserere sig paa Spiserørets og Tarmens 

 ydre Flade, Tab. XIX. Fig. 2, 3, 4. Herved deles Krops- 

 hulheden i 12 Kamre, Tab. XIX. Fig. 2, 3, 4 a, der kom- 

 municere med hverandre igjennem en liden. halvmaane- 

 formig Aabning (Oral-Stomata), som tindes paa Septa netop 

 der. hvor de fæste sig paa Mundskiven; forovrigt synes 

 Kamrene at være aflukkede. Fortil. eller foroven, omkring 

 Spiserøret ere de meget brede, men jo mere de nærme 

 sig den bagerste Ende. desto trangere blive de, saa at de 

 omkring Rectum ere yderst trange. Septumerne staa lige 

 langt fra hverandre, ere ikke parrede, ligesaalidt som der 

 er noget af dem. der kan betragtes som Retningsseptum, 

 Tab. XIX. Tab. 2. 4. Paa et Exemplar syntes nogle 

 Septa at Mere noget afvigende fra de øvrige, idet de vare 

 noget kortere, saa Afstanden imellem Kropsvæggen og 

 Tarmen blev mindre, og de tilsvarende Kamre som Folge 

 deraf trangere; men det tor hænde. at denne Afvigelse 

 var opstaaet ved en uregelmæssig og voldsom Kontraktion, 

 saa man Intet kan slutte deraf. 



Den norske Nordhavsexpedition, 1». O. Danielssen: Actinida, 



consequently between each two septal insertions, an extremely 



fine fissure about 2'"'" in length (Pl. XVIII. fig. 7 e). and, 

 we shall subsequently see, it leads right into the rectum. 

 The inner surface of the gullet-tube is longitudinally folded 

 and the folds are relatively very broad (Pl. XVIII. fig. 

 6 a : as the gullet-tube passes over into the intestine the 

 folds become narrower, but a little way back in the 

 intestine they project more forward and assume alun ist 

 the foliaceous form (Pl. XVIII, fig. (i b). whilst they in 

 the posterior part (rectum) become extremely narrow. 

 stand .-leser together, and are present in far greater 

 abundance (Pl. XVIII, fig. 6 c). 



The covering of the body is formed of a mucous mass 

 on whose exterior surface [scattered grannules of sand are 

 seen to be entrenched, whilst the interior surface is 

 smooth, and has no organic connection with the integu- 

 ment of the body. The latter has a pretty thick eetoderm. 

 consisting of a laver of long, narrow, ciliating cylinder-cells 

 with nucleus and nucleus-corpuscle (Pl. XVIII, fig. 8 a). 

 Between the cells, and partly covered by them. claviform 

 unicellular mucous glands are observed (Pl. XVIII, fig. 

 8 b), also a multitude of nematocysts (Pl. XVIII. fig. 8 c). 

 These last are especially richly present on the tentacles 

 and oral disc. Inside of the eetoderm there is a fibrillous 

 connective-tissue laver (Pl. XVIII, fig. 8 d) rich in con- 

 nective-tissue bodies witli prolongations, and also nutritory 

 ducts. Towards the inner surface of this connective-tissue 

 there is found a rather narrow belt of circular muscles 

 which appear to be situated in bundles but are not mueh 

 developed (Pl. XVIII, fig. 8 e). On the inner surface of 

 the connective-tissue longitudinal and transversal muscles 

 are secured (Pl. XVIII, fig. 8 /), aud are covered with 

 cylinder-epithelium (Pl. XVIII, fig. 8 g). 



There are 12 septa, which have their origin in the 

 inner wall of the body and extend quite from the anal 

 aperture and up to the under surface of the oral disc, to 

 which they attach themselves, whilst, also, they all insert 

 themselves on the exterior surface of the gullet-tube and 

 intestine (Pl. XIX, fig. 2, 3, 4). The cavity of the body 

 is thus divided into 12 chambers (Pl. XIX, figs. 2, 3, 4 a) 

 that communicate with each other through a small semi- 

 lunar opening (oral-stomata) which is found on the septa. 

 exactly at the point where they attach themselves to the 

 oral disc ; the chambers appear otherwise to be closed. 

 Anteriorly, or at the top round the gullet-tube; they are 

 very broad. but the more they approach to the posterior 

 extremity the narrower do they become, so that around the 

 rectum they are extremely narrow. The individual septa 

 are placed at uniform distances apart, and not in pairs, 

 whilst, also, there are none of them that can bo considered 

 as directive septa (Pl. XIX, figs. 2, 4). In one specimen 

 a few septa appeared to be somewhat different from the 

 rest as they were a little shorter, so that the distance 

 between the wall of the body and the intestine became 

 less, and, as a consequence of that, the corresponding cham- 

 bers became narrower, but it may perhaps be, that this 

 difference has arisen from an irregular and violent 



20 



