17 



Familie Sagartidæ 

 Stelidiactis ' Mopsiæ n. g. et sp. 



Tab. II, Fig. 4, ri; Tab. VIII, Fig. 7—11. 



Fodskiven er aflang, 34""" laup:, tyk og omklamrer 

 næsten ganske en Gren af Mopsia borealis, saa at der kun 

 er en Spalte af et Par Millimeters Bredde, hvori Grenen 

 ligger blottet, Tab. II. Fig. 4. 5. Den ombøiede Rand er 

 foldet, og Folderne 1 udgjør 12 paa hver Sule af Grenen, 

 Tab. VIII, Fig. 9. Imellem denne og Fodskivens Fnder- 

 flade er et tyndt, membranøst, stærkt klæbende Hudlag, der 

 er afsondret afFodskiven og omgiver endogsaa Størstedelen 

 af den blottede Del af Grenen, som ligger i Foden. 



Kroppen er omtrent 12""" hoi. cylindrisk; den har en 

 tast Konsistens, er glat og glindsende med 24 stærke 

 Længderibber, hvorimellem ligesaa mange dybe Furer. Tab. 

 II, 4. 5; Tab. VIII, Fig. 7. I disse Furer sees hist og 

 her uden nogen Regel mæssighed smaa, aflange Spalter, 

 Cinclides, Tab. VTII, Fig. 8. Kroppen antager stundom 

 en næsten elliptisk Fonn ved Dyrets Kontraktioner, og 

 dens øverste Rand er tyk og tentakulær. 



Mundskiven er 12""" i Gjennemsnit. rund. stærkt 

 hvælvet, saa at den til enkelte Tider danner en Konus. 

 paa hvis Ende den aflange Mundaabning sees. Tab. II. 

 Fig. 5. Mundlæberne ere foldede og Mundvigene glatte. 

 temmelig luede. Fra Munden og ben til Tentaklerne ud- 

 gaa straaleformigt 24 Folder, hvorimellem ligesaa mange 

 Furer. Tab. II. Fig. 4; Tab. VIII, Fig. 7. Ogsaa Mund- 

 skivens Hud er tyk. fast og uigjennemsigtig. 



Tentaklerne ere 24. retraktile, sidde i en Række paa 

 Kroppens øverste Rand. ere korte konisk tilspidsede og 

 tykke ved Granden. Kroppens Rand kan trække sig over 

 Mundskiven og skjule denne ganske 



Kolumnens Væg er temmelig tyk; dens ydre Flade 

 har sit sædvanlige Cylinderepithel med Cilier, og imellem 

 Cellerne tindes flaskeformede, encellede Slimkjertler. samt 

 Nematocyster. Indenfor Ectodermet er et fast, fibrillært 

 Bindevæv, i hvis Midte sees cirkulære Muskelfibre, som 

 ligge i Bundter. der paa Tversnit frembyde et smukt, net- 

 formigt Udseende. Paa Bindevævets indre Flade sees 

 Længdemuskler. som strax gaa over paa Septa og ere be- 

 klædte med et Endothel. der ikke frembyder noget særegent. 



De principale Septa. tier fæste sig paa Svælget, ere 

 6 Par. imedens de secundære, ufuldstændige Septa ere 



1 aTY,/.i'8to-i = en Hilen Seile. 



Oen muske Nordhavsexpedition. D. C. Danielssen : Actinida. 



Family Sagartidæ. 

 Stelidiactis ' Mopsiæ, n. g. et sp. 



Pl. II, figs. 1. ri; Pl. VIII, figs. 7—11. 



The pedal disc is oblong, o4""" in length, and almost 

 completelv enclasps a branch of Mopsia borealis. so mucb 

 so that there is only a fissure of a couple of millimetres 

 in breadtb in which the branch is left exposed (Pl. II. 

 figs. 4, 5). The bent margin is folded, and there are 12 

 folds o„ eacb side of the branch (Pl. VIII. fig. 9). Be- 

 tween it and the under-surface of the pedal disc there is 

 a thin. meinbranous. stronglv glntinous, integumental laver, 

 which is deposited from the pedal disc, and even surrounds 

 the greater part of the exposed portion of the branch 

 contained in the base. 



The body measures about 12""" in height, and is 

 cylindrical. It bas a firm consistency, is smooth and shin- 

 ing. and has 24 strong longitudinal ribs between which 

 there are a similar number of deep furrows (Pl. II, figs. 4. 

 5; Pl. VIII. fig. 7). In these furrows, but without anv 

 regularity, theie are seen, here and tliere. small oblong 

 fissures, cinclides (Pl. VIII, fig. 8). The body sometimes 

 assumes an almost elliptical form during the animals con- 

 tractions. Its uppermost margin is thick and tentacular. 



The oral disc measures 12'""' from side to side. is 

 round, strongly arcuate, so that it sometimes forms a cone, 

 on whose extremity the oblong oral aperture is seen (Pl. 

 II, fig. 5). The oral labiæ are folded. and the oral angles 

 are smooth and rather broad. From the mouth. 24 folds 

 radiate to the tentacles, and between thorn there are the 

 same number of furrows (Pl. II. fig. 4; Pl. VIII. fig. 7). 

 The integument of the oral disc is also thick, firm, and 

 opaque. 



The tentacles are 24 in number. and retractile; they 

 are placed in one series on the uppermost margin of the 

 body, are short, conically "acuminated, and thick at the base. 

 The margin of the body can draw itself over the oral disc 

 and completelv conceal it. 



The wall of the cdlumn is rather thick; its exterior 

 surface has the usual cylinder-epithelium with eiliæ; and be- 

 tween the eells. bottle-shaped, unicellular mucous glands. 

 as well as nematocysts, are found. Inside of the ectoderm. 

 there is a finn fibrillar connective-tissue, in wdiose middle 

 circular muscle-fibres are observed lving in fasciculi; in 

 transverse sections these present a beautiful reticulated 

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

 longitudinal muscles are seen passing immediately over 

 to the septa, and clad with an endothelium that does not 

 present anything remarkable. 



The principal septa. which are attached to the æso- 

 phagus, consist of (i pairs; whilst the secondary imperfect 



OTi/i^ioi == A little ]>illav or column. 



