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fæste; men maa være enige med R. Lankester deri, at 

 disse Knopper formentlig ere frembragte ved Kunst. 



De saakaldte Segmentalorganer — brune Blærer, 

 brune Rør. — Hos Sipunculiderne findes som bekjendt, ial- 

 mindelighed to, men hos enkelte Arter kun et, dels blære- 

 formigt, dels rørformigt Organ, der ved sin bredere Del er 

 fæstet til Bugfladen, medens den smalere Ende hænger frit 

 i Kropshulheden. Disse Organer aabne sig udad paa Bug- 

 fladen, hvorom Alle ere enige, medens de ifølge enkelte 

 Forskere skulle have en Pore paa den frie Ende, og efter 

 Andre f. Ex. Semper og Jourdain en tragtformig Aab- 

 ning nær Befæstningsstedet. De have en noget forskjellig 

 Farve, dels brun, gul, orangegul, dels næsten vandklar 

 f. Ex. hos Sipunculus norvegicus, hvilken Farve væ- 

 sentligen afhænger af deres Indhold, hvori stundom findes 

 fine Sandkorn. De ere stærkt musculøse, og paa deres 

 indvendige Flade beklædte med et cilierende Epithel. Vi 

 staa her atter over for Organer, om hvis Function der 

 har hersket og fremdeles hersker megen Tvivl. De have 

 været antagne snart for Testikler, snart for Æggestokke, 

 alt eftersom man har fundet Spermatozoer eller Æg i 

 dem, snart ere de blevne anseede for Respirationsorganer, 

 snart for Secretionsorganer, og endelig for Oviducter, lig 

 Segmentalorganerne hos Anneliderne, hvilken sidste An- 

 tagelse fik en stærk Støtte i Sempers Iagttagelser paa 

 flere tropiske Sipuncler, hos hvilke han skal have seet 

 Æggene passere fra Kropshulheden ind igjennem den af 

 ham beskrevne traktformige Aabning for at komme ind 

 i de nævnte Organer, og der end mere udvikles. — Paa 

 de Exemplarer, vi have undersøgt, saavel af Slægten 

 Sipunculus som Slægterne Phascolosoma og Onchnesoma, 

 har det ikke været os muligt at opdage nogensomhelst 

 anden Aabning for disse Organer end den, der findes paa 

 den udvendige Bugflade, og som er forsynet med en liden 

 Sphincter. Det har rigtignok stundom seet ud som om 

 der var en Aabning paa den frit i Kropshulheden svøm- 

 mende Ende; men det har ved streng Undersøgelse vist 

 sig at være en Grube, der faar en skuffende Lighed med 

 en Porus, som fremkaldes ved Muskelcontractioner, og 

 som hyppig opstaar og forsvinder igjen. Heller ikke 

 Brandt har været istand til at opdage nogen Aabning, 

 hverken paa den fri bagerste eller paa den forreste Ende, 

 og det uagtet han har gjort flere Injectioner. Flere Na- 

 turforskere have imidlertid iagttaget dels Æg, dels Sper- 

 matozoer i større og mindre Mængde indeni disse Orga- 

 ner, hvilket vi aldrig have seet, — og forsaavidt Æggene 

 og Zoospermerne ikke dannes der, har Spørgsmaalet været, 

 hvorledes de skulde være komne ind, naar ingen Aabning 

 existerer, hvorigjennem de kunde passere. Vi kunne intet 

 tilfredsstillende Svar give herpaa; men det forekommer 



sites. Our researches give us no opportunity for deciding 

 anything with respect to these bodies; only we have seen 

 that they are present in very small numbers, in the spe- 

 cies of Phascolosoma which we have examined. That 

 the ciliæ on these remarkable „töpfchen" should be 

 furnished with a knob, as Brandt describes them to be, 

 under the name „ciliæ vibratoriæ capitatæ u , we have not 

 been able to ascertain; but we must agree with Lan- 

 kester, that their knobs are probably produced artificially. 

 The so-called segmental organs — brown vesicles, 

 brown canals — are, as is well known, found generally 

 two in number in the Sipunculidæ; but in some species 

 there is only one partly visicular, partly tubular organ, 

 which at its broader part is attached to the ventral 

 surface, while the narrower extremity is suspended freely 

 in the perivisceral cavity. These organs have their ope- 

 ning outwards on the ventral surface, as to which all are 

 agreed; while, according to some naturalists, they are 

 said to have a pore at the free extremity, and according 

 to others, for instance Semper and Jourdain, a funnel- 

 shaped aperture near the point of attachment. They 

 have a very different colour, sometimes brown, yellow, 

 orange yellow, and sometimes nearly pellucid, as for in- 

 stance in the Sipunculus norvegicus, the colour depending 

 chiefly on their contents, among which there are some- 

 times found fine grains of sand. They are strongly mus- 

 cular, and on their interior surface covered with a cilia- 

 ting epithelium. We have here again before us organs, 

 as to the functions of which there has existed, and still 

 exists, much doubt. They have been regarded sometimes 

 as testicles, sometimes as ovaries, accordingly as sperma- 

 tozoa or ova have been found in them; sometimes they 

 have been taken for organs of respiration, for organs of 

 secretion, and finally for oviducts, like the segmental or- 

 gans in the annelides, which last assumption was strongly 

 supported by Semperas observations on several tropical 

 Sipunculi, in which it is said that he saw the ova pass 

 from the perivisceral cavity through the funnel-shaped 

 opening described by him, in order to enter the organs 

 in question and there to be further developed. In the 

 specimens we have examined, as well of the genus Si- 

 punculus as of the genera Phascolosoma and Onchne- 

 soma, it has not been possible for us to discover any 

 other opening whatever for these organs, excepting that 

 which exists in the exterior ventral surface, and which 

 is furnished with a small sphincter. There has indeed 

 sometimes appeared to be an aperture at the extremity 

 which swims freely in the perivisceral cavity; but on strict 

 examination, this apparent aperture has always proved 

 to be a hollow, with a deceptive resemblance to a pore, 

 produced by muscular contraction, and frequently disap- 

 pearing and recurring. Neither has Brandt been able 

 to discover any aperture on the free posterior extremity 

 nor on the anterior extremity; and that notwithstanding 

 he has made several injections. Several naturalists have 

 however observed somtimes ova, and sometimes sperma- 

 tozoa in greater or smaller numbers inside of these or- 



