136 



giver, som sædvanligt, en Mængde Grene, hvoraf de, der 

 gaa til Spiserøret, ere de længste. Spiserøret meget langt 

 og paa den forreste Del forsynet med et slangeformigt, 

 contractilt Kar (Fig. 43 k). Tarmkanalen bestaar af en 

 Mængde tæt til hinanden sluttende Vindinger, der bagtil 

 ikke ere befæstede, hvorimod de paa Siderne have 3 Til- 

 hæftninger; af disse er dog den, der befæster den 1ste 

 Tarmslynge, den længste og stærkeste. Rectum er meget 

 kort og ved mange Muskelfibre stærkt fæstet til Huden. 

 Desforuden findes en rudimentær Spindelmuskel, der op- 

 hører paa 3die eller 4de Tarmslynge. Segmentalorga- 

 nerne to, frie og tildels snoede. Generationsorganet tager 

 sin Begyndelse ved den nederste Del af Spiserøret og 

 omgiver næsten som en Kapsel hele Tarmspiralen (Fig. 

 43 g, g). Kropshulheden og de i den indesluttede Organer 

 ere beklædte med Peritoneum. 



Dyrets Længde 30—50 Mm., hvoraf omtr. 20— 30 Mm. 

 indtages af Snabelen. Farven blaalighvid eller perlegraa. 



Findested : Lofoten, Tromsø, Komagfjord, Hammer- 

 fest, Grønland og Spitsbergen. Dybden: Sars angiver 

 30—40, ja indtil 300 Favne. Danielssen 30—60, sandig 

 Bund. 



Ogsaa for denne Arts Vedkommende have vi forskaffet 

 os Originalexemplarer og derved forvisset os om, at Phas- 

 colosoma Ørstedii, Kef. ikke er nogen fra Sars's Phas- 

 colosoma margaritaceum forskjellig Art. 



FORKLABING OVER FIGURERNE. 

 Tab. 15, Fig. 43. Phascolosoma margaritaceum, aabnet. dr Dor- 



salretractor; vr Yentralretractor; g, g Generationsorganet; 



o slangeformigt Organ; h contractilt Kar. 

 Fig. 44. Et Stykke af Æggestokken tilligemed sine Udkrængninger, 



der indeslutte Æg i forskj eilige Udviklingsstadier. 



PHASCOLOSOMA (SYRINX) HABVEI1, Fore. 



(Tab. 15, Fig. 41-42). 

 British Starfishes, Pag. 249. 



Phascolosoma margaritaceum, Keferstein. 

 Nachricht, d. k. Ges. d. Wissensch. Gøttingen, 1S65, Pag. 201. 

 Zeitschr. f. wiss. Zoologie, 15 B., Pag. 430, Taf. XXXI, Fig. 9, 

 Taf. XXXII, Fig. 28, 29. 



Sipunculus ooscurus, Quatf. (fide Grube). 

 Histoire nat. des annelés marins et d'eau douce, Tom. 2, Pag. 

 216, PI. 16, Fig. 16, 17. 



Kroppen omtr. 40 Mm. lang, cylindrisk, næsten 

 glat, besat med yderst smaa Papiller, der paa den conisk 

 tilspidsede Bagende og ved Grunden af Snabelen ere mere 

 sammentrængte og danne ligesom to brune Belter, som 

 have et reticuleret Udseende. Huden svagt perlemor- 

 glindsende, blød og halv gjennemskinnende. Snabelen 

 temmelig kort, omtrent af Kroppens Længde, forsynet 

 med flere Eækker Tentakler; paa dens forreste Ende 

 bagenfor Tentakelkrandsen en glat Ring, og nedenfor 



boscis. At the basis of each ventral retractor, there is^ 

 a thin serpentine organ containing ova in different stages 

 of development (fig. 43 o). The nervous cord furnishes, 

 as usual, a number of branches, of which those that go 

 to the oesophagus are the longest. The gullet is very 

 long, and on the anterior part provided with a serpentine, 

 contractile vessel (fig. 43 k). The intestinal canal consists 

 of a number of close-lying circumvolutions, which are not 

 attached behind, but have on the sides 3 attachments, 

 of which the longest and strongest is that which fastens 

 the first circumvolution of the intestine. The rectum is 

 very short, and strongly attached to the skin by many 

 muscular fibres. Moreover there is a rudimentary fusi- 

 form muscle, which ceases at the 3rd. or 4th. circum- 

 volution of the intestine. The segmental organs two, free 

 and partly twisted. The organ of generation takes its 

 beginning at the lower part of the oesophagus, and sur- 

 rounds, nearly like a capsule, the whole intestinal spiral 

 (fig. 43 g, g). The perivisceral cavity and the organs 

 contained in it, are covered with the peritoneum. 



The length of the animal 30—50 Mm. of which 

 about 20—30 Mm. occupied hy the proboscis. The color 

 bluish white or pearl-grey. 



It is found at Lofoten, Tromsø, Komagfjord, Ham- 

 merfest, Greenland and Spitsbergen. The depth given by 

 Sars is 30—40 and even up to 300 fathoms. Danielssen 

 states 30—60, sandy bottom. 



Also in respect to this species, we have procured 

 original specimens, and thereby ascertained that Phas- 

 colosoma Ørstedii Kef. is not any different species from 

 Sars's Phascolosoma margaritaceum. 



EXPLANATION OF THE FIGURES. 



Tab. 15, fig. 43. Phascolosoma margaritaceum, opened, dr dorsal 

 retractors ; vr ventral retractors ; g, g organ of genera- 

 tion; o serpentine organ; h contractile vessel. 



Fig. 44. A part of the ovary, together with its follicles containing 

 ova in various stages of development. 



PHASCOLOSOMA (SYRINX) HARVE11, Foeb. 



(Tab. 15, fig. 41—42.) 

 British Star-fishes, p. 249. 



Phascolosoma margaritaceum, Keferstein. 

 Nachricht d. k. Ges. d. "Wissensch. Göttingen, 1865, p. 201. 

 Zeitschrift f. wiss. Zoologie, 15 B., p. 430, Taf. XXXI, fig. 9, 

 Taf. XXXII, fig. 28, 29. 



Sipunculus obscurus, Quatf. (fide Grübe). 

 Histoire nat. des annelés marins et d'eau douce. Tom. 2, p. 216, 

 PI. 16, fig. 16, 17. 



The body about 40 Mm. long, cylindrical, nearly 

 smooth, covered with extremely small papillae, which on 

 the conically tapered posterior end, and on the base of 

 the proboscis, are more closely compressed, and form, 

 as it were, two brown belts, which have a reticulated 

 appearance. The skin is slightly lustrous like mother of 

 pearl, soft and semi-transparent. The proboscis rather 

 short, about the length of the body, having several rows- 

 of tentacles; on its anterior extremity, behind the ten- 



