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hed, at hos Ægir er der en fuldstændig udviklet Tarm, 

 som munder ud i en virkelig Anus. uafhængig af Krops- 

 hulheden, imedens hos Otenophorerne Svælgrøret aabner 

 sig i Gastrovascularrummet. Slægten Fenjas Tarmapparat 

 er deriraod ganske afstængt fra Kropshulheden og fjerner 

 sig forsaavidt længere fra Ooelenteraterne end Ægir. 



Skal Coelomet være det Afgjørende, saa er det klart, 

 at mine to Slægter maa udaf Coelenteraternes Rækker; 

 men hvor de da skulle henføres, ved jeg sandelig ikke at 

 angive. Det tør imidlerlid hænde, at man har tillagt det 

 saakaldte Gastrovascularapparat en altfor stor systema- 

 tisk Betydning ved at betegne hele den Dyregruppe. Cuvier 

 kaldte Zoophyter, som Ooelenterater. Hvad der kaldes 

 Svælgrør hos Actiniderne er muligens en begyndende 

 Tarmdannelse, og de. Kamre, som tindes til Siderne af 

 Svælgrøret, kunne maaske betragtes som en begyndende 

 Coelqmdannelse. Tydeligere bliver dette hos Otenophorerne, 

 hvor Svælgrøret ikke blot har Formen, men ogsaa Funk- 

 tionen af en virkelig Fordøielseskanal, om den end mangler 

 Anus og staar i direkte Kommunikation med Gåstrovascular- 

 hulheden. I ethvert Fald er der her i Grunden ikke langt 

 til en fuldstændig Sondring imellem Tarm og Kropshulhed. 

 Muligvis vil man selv inden Actinidernes Gruppe kunne 

 paavise en forskjellig Udvikling af Svælgrøret og en her- 

 med i Forbindelse staaende mere eller mindre stærk Sondring 

 af den saakaldte Gastrovascularhulhed, hvorved Forholdet 

 hos Slægterne Ægir og Fenja ville kunne opfattes som 

 Enderesultatet af en Udviklingsproces, der allerede er for- 

 beredt hos andre Actinider. Men sikker Kundskab om 

 disse Forhold vil neppe kunne vindes uden gjennem em- 

 bryologiske Undersøgelser ; thi da vil det vise sig, om de 

 udvikle sig som virkelige Ooelenterater, eller om de muligens 

 vise sig at tilhøre enten Pseudocoelier eller Enterocoelier. 

 Jeg vil imidlertid lade mig nøie med at henfore dem til 

 Actinidernes store Afdeling, men har dog fundet det nød- 

 vendigt at danne en særskilt Stamme (Tribus) for dem. 



gastro-vascular spaee by hvo narrow lateral fissures. But 

 what, Innvever, marks an important difterenee is. the cir- 

 cumstance, that in Ægir there is a perfectly developed 

 intestine which opens into a real anus independent of the 

 body-cavity, whilst in Ctenophora the gullet-tube opens 

 into the gastro-vascular spaee. The intestinal apparatus 

 of the genus Fenja is. on the other hand. quite shut off 

 from the body cavity, and therefore distinguishes itself 

 more from the Coélenterata than Ægir does. 



If we make the Coelome the decisive feature, it is 

 theu evident, that my two species must Vie rcmoved from 

 the ranks of the Coélenterata, but where they should then 

 be placed I can really not indicate. It may. however, 

 be the case, that ton much stress has been laid on the 

 so-called gastro-vascular apparatus as a systematic feature 

 in naming the whole of the animal group that Cuvier called 

 Zoophytes, Coélenterata. What is called gullet-tube in 

 Actinida is possibly a rudimentary intestinal formation, and 

 those at the sides ot' tlie adjoiniug chamhers may perhaps 

 be considered as a beginning formation of the coloeme. 

 This is still more distinct in the Ctenophora. where the 

 gullet-tube not only has the form of an intestine. but also 

 the function of a real digestive canal, even though anus is 

 awanting, and is placed in direct communication with the 

 gastro-vascular cavity. In any case there is. Iiere. in 

 reality. no great step to a complete separation between 

 the intestine and the body-cavity. Probably, even in the 

 group of the Actinida it may be possible to show a dif- 

 ferent development of gullet-tube, and. in connection with 

 it. a more or less distinct separation of the so-called gastro- 

 vascular cavity: tiurs leading the relation in the genera 

 Ægir and Fenja to be regarded as the final stage of a 

 process ot' development that has already begun in other 

 Actinida'. But certain knowledge in respect of those rela- 

 tions will scarcely be obtained except by investigations 

 of embryons, as. then. it will be seen whether they develope 

 themselves as genuine Coélenterata. fir whether they pos- 

 sibly show themselves to belong to either Pseudocoelia or 

 Enterocoelia. In the meantime I am satisfied with their 

 assignment to the great division Actinida. but have, 

 however. found it necessary to form a new race (tribus) 

 for tliem. 



