83 



en Bredde af 3 -4""". imedens de øvrige, almindelige Polyper 

 indtage paa samme Sted lidt over 1""". Tentaklerne ere 

 sammenlimede, og deres Ender indbøiede, hvorved Adgan- 

 gen til Mundaa,bningen er fuldstændigt spærret. Ribberne 

 og Furerne paa den ydre Kropsvæg ere stærkt fremtræ- 

 dende, Fig. 5. Disse svangre Polvper, der siden skulle 

 nærmere omtales, gaa umiddelbart over i Grenen uclen at 

 forene sig med nogen anden Polyp. 



Ånatomisk-histologisk Undersøgelse. 



Stammen har en ydre Beklædning, Eetodermet, dannet 

 af flere Lag polyædriske Celler. I det indre Lag sees 

 imellem Ectodermcellerne fiaskeformede Celler med en 

 Udløber og en aflang Kjerne, omgiven af et fintkornet Indhold 

 — encellede Slimkjertler — ; desforuden er i Eetodermet 

 afleiret en Mængde Spilder, der ogsaa findes i det inden- 

 for værende hyaline Bindevæv. men altid omgivne af Ectoderm- 

 celler. 



I Bindevævslaget findes Bindevævslegemer med en 

 eller flere Udløbere, der korrespondere med hverandre 

 samt Ernæringskanaler. Ved at undersøge de svangre 

 Polyper viser det sig, at Mundaabningen er tillukket ved 

 en slimet Masse, at Svælget er i høi Grad udvidet, dets 

 Vægge fortykkede, Fig. 6, a, og Hulheden opfyldt af Em- 

 bryoner i forskjellige Udviklingsstadier. — dog ere de, 

 der ligge nærmest Mundspalten, videst komne, hvorfor 

 ogsaa den øverste Del af Svælget er mest udvidet, Fig. 

 6, b. I Mavehulheden sees endnu enkelte uudviklede Æg, 

 indesluttede i de stilkede Kapsler, der tåge deres Udspring 

 fra Septula. 



Det er et mærkeligt Forhold, som her optræder, idet 

 Svælget virkelig omdannes til en Uterus, hvori Ungerne 

 udvikle sig. Paa flere Polyper iagttages, at den bagerste 

 Kropsdel, just der, hvor den gaar over i Grenen, er op- 

 svulmet, imedens den forreste Del endnu er normal ; men 

 Tentaklerne ere begyndte at lime sig sammen, og deres 

 Ender ere indkrængede. Naar disse Polyper aabnes, 

 findes Æg i forskjellige Stadier, men alle indesluttede i 

 deres stilkede Kapsler, sædvanlig et Æg i hver Kapsel. 

 Svælget er ikke udvidet og er enten tomt eller indeholder 

 nogle Foraminiferer, Rester af de indtagne Fødemidler. 

 Mange af Æggene have gjennemgaaet Furingen, ere altsaa 

 befrugtede, men den egentlige Fosterdannelse er neppe 

 begyndt. Saasnart denne tager sin Begyndelse, forlader 

 Larven, endnu indesluttet i Ægget, Kapselen, og Svælget 

 er nu præpareret til at modtage Ungen, for at den der 

 kan gjennemgaa sin videre Udvikling. Mundaabningen er 

 ganske lukket ved det omtalte Slim, saa Polypen kun kan 

 faa sin Næring igjennem den i Gren eller Stamme forlængede 



it attains a breadth of 3— 4 mm , whilst the rest of the 

 general body of the polyps attain, in the same situation, 

 only a little more than l mm in breadth. The tentacles 

 are glued together, and their extremities are curved inwards, 

 causing the access to the oral aperture to be completely 

 closed. The ribs and the grooves on the exterior wall of 

 the body are strongly prominent (fig. 5). These fructi- 

 fied polyps, which later on shall be further discussed, pass 

 directly over into the branch without uniting themselves 

 to any other polyp. 



Anatomo-histological Examination. 



The stem has an exterior covering — the ectoderm 



— formed of several layers of polyheclrical cells. In the 

 inner layer, between the ectodermal cells, bottle-shaped cells 

 are seen, with a prolongation, and an oblong nucleus 

 surrounded by a minute granular substance — unicellular 

 mucous glands — there is, besides, entrenched in the 

 ectoderm, a multitude of, spicules; these are also found in 

 the hyaline connective-tissue situated on its inner side, but 

 always surrounded by ectodermal cells. 



In the connective-tissue layer, connective-tissue cor- 

 puscles having one or more prolongations which correspond 

 with each other, and also nutritory ducts, are found. On 

 an examination of the fructified polyps, it is seen that 

 the oral aperture is closed by a mucous mass; that the 

 gullet is, in a high degree, dilated, its walls tumefied 

 (fig. 6, a), and the cavity occupied by embryons in various 

 stages of development, whilst those of them, hoAvever, which 

 are situated closest to the oral fissure are most developed; 

 consequently, therefore, the uppermost part of the gullet is 

 most dilated (fig. 6, b). In the gastral cavity there are, 

 further, observed, a few undeveloped ova, enclosed in the 

 pedunculated capsules which issue from septula. 



It is a very remarkable state of relations which, 

 here, exists, because the gullet really becomes transformed 

 into a uterus in which the young clevelope themselves. 

 In several polyps, it may be observed that the posterior 

 part of the body, just at the point where it passes over 

 into the branch, is tumefied, Avhilst the anterior part still 

 remains in the normal condition, but its tentacles have 

 begun to become glued together, and their extremities to 

 be curved inwards. "When these polyps are opened, ova are 

 found in various stages of development, but all of them 

 enclosed in their pedunculated capsules, usually one oVum 

 in each capsule. The gullet is not dilated, and is, either, 

 empty, or contains some foraminifera, remnants of the 

 nutritive substances absorbed. Many of the ova have under- 

 gone the segmentation and are therefore impregnated, but 

 the true fætal-formation has scarcely commenced. As soon 

 as it commences, the larva — ■ still enclosed in the ovum 



— relinquishes the capsule, and the gullet- is now prepared 

 for the reception of the young, to undergo, there, their 



U* 



