123 



Organ, men som istedetfor at indeholde Æg, var udfyldt 

 med en utallig Mængde traadformige Legemer, som vi 

 ikke kunde faa til Andet end Zoo spermer; forøvrigt var 

 Bygningen den samme, som vi have omtalt ved Ægge- 

 stokken. At Hannerne hos Sipunculiderne maa være tem- 

 melig sjeldne i Forhold til Hunnerne, have vi Grund til 

 at tro deraf, at hlandt de mangfoldige Phascolosomaer, vi 

 have undersøgt, have vi kun paa 1 Spiritusexemplar, og 

 1 levende fundet Zoospermer, hvilket stemmer overens 

 med Claparéde's Iagttagelser. 



Til Slutning skulle vi omtale to Organer, som vi con- 

 stant have fundet ved Grunden af Bugretractorerne (et 

 ved hver Retractor) hos Phascolosomerne, og som vi have 

 beskreve ved hver enkelt Art (se den specielle Beskri- 

 velse over Phascolos.). Disse Organer, der ere traadfor- 

 mige, bugtede Legemer, som omgive Retractorens Basal- 

 del, have indeni sig en Kanal, hvori vi nogle Gange have 

 fundet Æg i forskj eilige Udviklingsstadier, medens vi of- 

 tere have fundet dem uden Æg. Allerede for flere Aar 

 siden tiltrak disse Organer sig vor Opmærksomhed, og 

 forunderligt nok har, saavidt os bekjéndt, ingen af de 

 Forskere, der have beskjæftiget sig med Sipunculiderne, 

 omtalt dem, førend vi nu for ganske nylig finde i en liden 

 Notits af Hubert Ludwig i hans Arbeide over Ægdannel- 

 sen i Dyreriget T ), at Semper skal have iagttaget disse Or- 

 ganer, og fremsat den Formodning, at de muligens vare 

 Genitalkj ertier. 



S1PUNCUL1BÆ. 



S1PUNCULUS NOMVEGICUS, Nobis. 

 (Tab. 13, fig. 7—10). 

 Sipunculus norvegicus, D. Forhandlinger ved de skandinaviske 

 Naturforskeres Møde i Christiania 1868, pag 541. 



Legemet cylindrisk, 60 Mm. langt og 20 Mm. i Om- 

 kreds, svagt ribbet paa langs og fint stribet paatvers. 

 Henimod den bagerste Del danner Huden en fremragende 

 Fold, der gaar som en Vold omkring Legemet, hvorved 

 opstaar en tydelig Glans, der er 9 Mm. lang (Tab. 13, 

 fig. 7). Dennes bagerste Ende er afrundet, og har paa 

 Midten en yderst fin Grube, hvori dog ingen Aabning er. 

 Foran Volden er Kroppen noget smalere, men udvider 

 sig fortil imod Snabelen, hvor den atter bliver smalere. 

 Fra Volden til Snabelens Begyndelse har Kroppen en 

 Længde af 35 Mm. Snabelen er omtr. 16 Mm. lang, tæt 

 besat med coniske Papiller, der staa i uregelmæssige Ræk- 

 ker, som tiltage i Tæthed imod dens Ende. Mundaab- 

 ningen danner en Tverspalte, og er omgiven af 8 temmelig 

 tykke hvidgule Tentakler, der ere næsten lancetformige 

 med afstumpede Ender og nedentil sparsomt lappede. 



l ) Arbeiten aus dem zoolog. -zootom. -Institut in Würzburg. 

 Semper 1874, p. 338. 



in the skin of these. What we have said of the ovary 

 applies in the main also to the testicle. We have in a 

 spirit specimen found an organ completely resembling an 

 ovary, but, instead of containing ova, filled with innumer- 

 able filiform bodies which we could not make out to be 

 any thing else than zoospermata. Otherwise the struc- 

 ture of the organ was the same as we have noticed in 

 the ovary. That the males in the Sipunculi must be rather 

 rare in proportion to the females, we have some reason 

 to believe; as among the numerous Phascolosomas we 

 have examined, we have only in one spirit specimen and 

 in one living specimen found zoospermata; which agrees 

 with the observations of Claparéde. 



In conclusion we shall notice two organs which we 

 have constantly found at the base of the ventral retractors 

 (one at each retractor) in the Phascolosoma, and which 

 we have described in each single species (see the special 

 description of Phascolos,). These organs, which are fili- 

 form, sinuous bodies surrounding the basal part of the 

 retractor, have in them a canal wherein we have some- 

 times found ova in different stages of development, while 

 we have more frequently found them without ova. Al- 

 ready several years ago these organs attracted our atten- 

 tion; and strange enough, so far as we know, not any 

 of the naturalists who have turned their attention to the 

 Sipunculides have mentioned them, until we find quite 

 recently, in a little notice by Hubert Ludwig in his work 

 on the formation of ova in the animal Kingdom l ), that 

 Semper is said to have observed these organs, and to have 

 put forth the supposition that they are possibly genital 

 glands. 



S1PUNGULIDÆ. 



SIPUNGULUS NORVEGICUS, Nobis. 

 (Tab. 13, fig. 7-10). 

 Sipunculus norvegicus, D. Forhandlinger ved de skandinavisk© 

 Naturforskeres Møde i Christiania 1868, p. 541. 



The body cylindrical, 60 Mm. long and 20 Mm. in 

 circumference, slightly ribbed longitudinally and finely 

 striped transversally. Towards the posterior part, the 

 skin forms a prominent fold, which goes like a ridge 

 round the body, whereby there is formed an evident glans 

 9 Mm. long (Tab. 13, fig. 7). The posterior end of 

 this is rounded, and has in the middle an extremely fine 

 hollow, wherein however there is no opening. In front 

 of the ridge the body is somewhat smaller, but enlarges 

 itself towards the anterior part to the proboscis, where 

 it again becomes smaller. From the ridge to the com- 

 mencement of the proboscis, the body has a length 

 of 35 Mm. The proboscis is about 16 Mm. long, thickly 

 covered with conical papillae standing in irregular rows, 

 which increase in density towards its extremity. The 

 oral aperture forms a transverse fissure, and is surrounded 



') Arbeiten aus dem zoolog.-zootom.-Institut in Würzburg. 

 Semper 1874, p. 338. 



