65 



lige saa lange som Kroppens hele Længde og ende traad- 

 formigt, saa at de under Bevarelsen viste sim im-rt Ham- 

 rende, Tab. IV. Fig. 1; Tab. XIII. Fig. 7. Hele den 

 øverste, nøgne Del af Kroppen med Tentakler og Mund- 

 skive kan fuldkommen trækkes ind i Skeden, der lukkes 

 ganske og antager Formen af en opretstaaende Kolle, Tab. 

 IV, Fig. 2. Naar den inkrusterede Skede fjernes, viser 

 den indenfor værende Hud sig at være foldet, ligesom den 

 øverste, nøgne Del af Kroppen, og som denne besat med 

 Længderækker af Sugevorter, Tab. XIII, Fig. 7 c. 



Farven. Skeden ergraahvid; indenfor den er Krops- 

 huden laxerod. hvilket ogsaa er Tilfældet med den nøgne 

 Del. Mundskiven og den indre Række af Tentaklerne ere 

 mørkere, medens de ydre Tentakler ved Grunden og paa 

 den aborale Flade have Kroppens Farve, men ere næsten 

 ganske hvide forresten. Tab. IV, Fig. 1 — 4. 



Den inkrusterede Del af Kroppen viser paa Tversnit. 

 at den inkrusterede Skede bestaar af to Lag; det ydre, 

 som er dannet af en tyk, seig, slimet Membran, hvori er 

 indleiret Lerklumper og Biloculiner, og et indre, der dan- 

 ner en fast. tynd, fibrillær Membran (Cuticula), som er 

 stærkt adhæreret til det indenfor værende Ectoderm. Dette 

 bestaar af temmelig korte, lidt forkroblede Cylinderceller 

 med Kjerne, men uden Cilier, og imellem Cellerne spredte, 

 encellede Slimkjertler. Indenfor Eetodermet, Tab. XIII, 

 Fig. 8 a. er et fibrillært Bindevæv. der ikke er meget bredt, 

 Tab. XIII Fig. 8 b, og i hvis Midte sees stærkt udviklede, 

 cirkulære Muskler, som danne Bundter, der især ere frem- 

 trædende baade paa Længde- og Skraasnit, Tab. XIII, 

 Fig. 8 c. Til begge Sider af de cirkulære Muskler er et 

 Belte, hvori sees Bindevævslegemer og fine Ernærings- 

 kanaler, Tab. XIII, Fig. 8 b. Paa den indre Flade af 

 dette Bindevæv sees Længdenmskler. beklædte med lange 

 Cylinderceller, som ere forsynede med Cilier. 



Paa den nøgne Del af Kroppen er Eetodermet tem- 

 melig bredt og bestaar af lange eilierende Cylinderceller. 

 imellem hvilke sees encellede Slimkjertler og en rigelig 

 Mængde Nematocyster. Eetodermet paa Mundskiven er 

 mindre rigt paa Nematocyster; derimod synes her Cilierne 

 at være længere end paa Kroppen, og i Bindevævet samle 

 de cirkulære Muskler sig omkring Mundaabningen og danne 

 Slut muskelen (Sphincter). 



Tentaklernes Ectoderm er overordentligt rigt paa 

 Nematocyster, især paa den aborale Flade, og indenfor 

 det ere stærke Længdenmskler leirede saaledes, at de rage 

 noget ind i Bindevævet. Paa dettes indre Flade findes et 

 yderst tyndt Lag Tvermuskler. der beklædes af Endothel- 

 celler. hvorimellem iamttamvs enkelte encellede Slimkjertler. 



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



are exceedingly long. indeed almost as long as the entire 

 length of the body. and terminate filamentously, so that 

 during movement they show themselves verv wavinglv (Pl. 

 IV. Hg. 1; Pl. XIII. fig. 7). The entire uppermost. bare 

 part of the body with the tentacles and oral disc. can be 

 completely withdrawn into the sheath, which then becomes 

 quite closed and assumes the form of a vertical club (Pl. 

 IV. fig. 2). AVhen the encrusted sheath is reinoved the 

 integument that lies inside of it shows itself to be folded 

 in similar manner to the uppermost bare portion of the 

 body. and, like it, it is also covered with longitudinal series 

 of suckers (Pl. XIII, fig. 7 r). 



The colour. The sheath is greyish-whitc; inside of 

 it the integument of the body is salmon-red colour, which 

 is also the case with the bare portion. The oral disc and 

 the inner series of the tentacles are darker in colour, whilst 

 the outer series of tentacles have, at the base and on the 

 aboral surface, the colour of the body, but are otherwise 

 almost quite white (Pl. IV, fig. 1 — 4). 



The encrusted portion of the body shows in trans- 

 versal sections, that the encrusted sheath consists of two 

 layers viz. the outer one formed of a thick, viscid, mucous 

 membrane in which pieces of elay and biloculina are em- 

 bedded; and an inner one that forms a finn. tliin, fibrillar 

 membrane (cuticulum) and is strongly adherent to the ecto- 

 derm lying inside of it. The latter consists of rather short, 

 slightly deformed cylinder-cells with nuclei but without 

 eiliæ, and between the cells unicellular mucous glands are 

 dispersed. Inside of the ectoderm (Pl. XIII, fig. 8 a) 

 there is a fibrillar connective-tissue which is not very broad 

 (Pl. XIII, fig. 8 b), and in whose middle strongly devel- 

 oped circular muscles are seen forming fasciculi, which 

 are especially prominent in both longitudinal and diagonal 

 sections (Pl. XIII, fig. 8 c). On both sides of the cir- 

 cular muscles there is a belt in which connective-tissue 

 corpuscles and fine nutritory ducts are observed (Pl. XIII, 

 fig. 8 b). On the inner-surface of this connective-tissue 

 longitudinal muscles are seen. clad with cylinder-cells fur- 

 nished with eiliæ. 



On the bare portion of the body the ectoderm is 

 rather broad. and consists of long. ciliating cylinder-cells. 

 between which unicellular mucous glands and a rich abund- 

 ance of nematocysts are observed. The ectoderm on «the 

 oral disc is less rich in nematocysts, but on the other hand 

 the eiliæ appear here to be longer than on the body, and 

 in the connective-tissue the circular muscles collect them- 

 selves around the oral aperture and form a sphincter. 



The ectoderm of the tentacles is exceedingly rich in 

 nematocysts, especially upon the aboral surface, and inside 

 of it powerful longitudinal muscles are embedded, in such 

 manner that they extend somewhat into the connective- 

 tissue. On the inner surface of the connective-tissue an 

 extremely tliin laver of transversal muscles is found. clothed 

 with endothelial cells between which a few unicellular 

 mucous glands are observed. 



