72 



Ectodermet afsondres Slim. oa; saa vælter Dyret sig paa 

 Bunden, eller det sætter Overfladen af denne i Bevægelse 

 med Tentaklerne, hvorved de fremmede Legemer fæste sig i 

 Slimet. Ectodermet er dannet af temmelig forkrøblede 

 Cylinderceller med Kjerne, men uden Cilier og fattige paa 

 Protoplasma. Tab. XIV, Fig. 9 «. Imellem Ectodermcel- 

 lerne sees hist og her encellede, kolbeformige Slimkjertler. 

 hvoraf flere ere tomme og sammenskrumpede. Indenfor 

 Ectodermet er et temmelig bredt Lag fibrillært Bindevæv, 

 forsynet med Bindevævslegemer , der have dels en, dels 

 flere Udlobere, samt fine Saftkanaler med deres Epithel. 

 Tab. XIV. Fig. 9 b, som bestaar af smaa, afla,nge Celler, 

 der ganske udfylde Lumenet, saaledes som jeg oftere har paa- 

 vist at være Tilfælde hos Coelenteraterne. Omtrent i Midten 

 af dette Bindevæv sees temmelig stærkt udviklede, cirkulære 

 Muskler, der danne fine Bundter. som synes paa enkelte 

 Steder at anastomosere med hverandre, Tab. XIV, Fig. 9 c, 

 og paa dets indre Flade ei- et Epithelialovertræk, bestaaende 

 af lange, cilierende Cylinderceller. Tab. XIV. Fig. 9 d. der 

 forresten bekleder hele Grastralhulheden med deri værende 

 Organer. 



Et Tversnit af den nogne Kropsdel viser et bredt 

 Ectodermlag, dannet af lange, cilierende Cylinderceller med 

 en aflang Kjerne og et rigt Protoplasmaindhold. Imellem 

 Cellerne ei' leiret en rigelig Mængde encellede, langstrakte 

 Slimkjertler. samt Nematocyster. Bindevævet er her som 

 paa den af Skeden indesluttede Kropsdel og ligesaa Endo- 

 thelet. imedens de mesodermale Cirkuhernmskler ere kanske 

 noget mere udviklede. 



Tentaklerne have paa deres ydre JFlade en stærk 

 Bekladning af Ectodermet, bestaaende af Cylinderceller. 

 ganske lig dem paa den nogne Kropsdel. imellem hvilke 

 ere encellede Slimkjertler og en overordentlig stor Mængde 

 Nematocyster, der aldeles skjule Ectodermcellerne; indenfor 

 disse er et Lag meget udviklede Længdemuskler, som ere 

 fæstede til Bindevævet, paa hvis indre Flade de transver- 

 selle Muskler ere leirede, beklædte af Endothelet. 



Der er 12 Par fuldstændige Septa, Tab. XIV. Fig. 10; 

 af disse synes 6 Par at være de principale. da de ere 

 stærkere byggede, have en kraftigere Muskulatur og ere 

 golde; desforuden er der -1 Par ufuldstændige Septa. Af 

 de li Par principale. fuldstændige Septa. er der 2 Par Ret- 

 ningssepta, som svare til Svælggruberne og ere meget brede; 

 hvert Pars Septa staa langt fra hinanden, saa at Intra- 

 septalrummet bliver meget bredt. Tab. XIV. Fig. 10 R. 

 Længdemusklerne ere fæstede paa den udvendige Flade af 

 hvert Septum, vende mod Interseptalrummet, ere meget 

 stærkt udviklede og danne henimod Svælgrøret, hvor de 

 opnaa den storste Tykkelse, store Buske, der rage langt 

 ind i Interseptalrummet. Tab. XIV, Fig. 10 a. De trans- 

 verselle Muskler ligge paa den indre Flade af Septuinet 



laver it becomes reproduced in this way viz. mucous is 

 deposited from the ectoderm. and the animal rolls itself on 

 the sea-bottom or stirs the surface of the bottom up 

 with its tentacles, causing the foreign bodies to attach 

 themselves to the mucous. The ectoderm is formed of 

 rather deformed cylinder-cells with nuclei but without 

 ciliæ and poor in protoplasm (Pl. XIV, fig. 9 a). Between 

 the ectoderm cells there are here and there seen unicel- 

 lular elaviform mucous glands, several of which are empty 

 and shrunk together. Inside of the ectoderm there is a 

 rather broad laver of fibrillar connective-tissue furnished 

 with connective-tissue corpuscles that have. partly one. 

 partly several prolongations, also fine nutritory ducts with 

 their epithelium (Pl. XIV. fig. 9 //) ; the latter consists 

 of small oblong cells that quite fill the channel in the same 

 way as I have frequently shown to be the case with 

 coelenterata. At about the middle of this connective- 

 tissue rather strongly developed circular muscles are seen, 

 forming fine fasciculi that appear in some places to anas- 

 tomose with each other (Pl. XIV. fig. 9 c), and upon its 

 inner-surface there is an epithelial covering consistini: of 

 long ciliating cylinder-cells (Pl. XIV. fig. 9 d), which further 

 clothes the entire gastral cnvitv and the organs lying 

 within it. 



A transversal section of the bare part of tire body 

 shows :i Innad laver of ectoderm, formed of long ciliating 

 cylinder-cells with an oblong Ducleus and a rich proto- 

 plasmic contents. Between the cells there are embedded a 

 rich abundance of unicellular, elongate mucous glands, also 

 nematocysts. The connective-tissue is here similar to that 

 of the part of the body enclosed in the sheath. and sn 

 also is the endothelium. whilst the mesodermal circular 

 muscles are. perhaps, a little more developed. 



The tentacles have, upon their outer surface. a strong 

 covering of the ectoderm, consisting of cylinder-cells. rpiite 

 like those on the bare part of the body, between which 

 there are unicellular mucous glands and an exceeding great 

 abundance of nematocysts that quite conceal the ectoderm- 

 cells; inside of these there is a layer of well developed 

 longitudinal muscles secured to the connective-tissue. upon 

 whose inner-surface the transversal muscles. clothed with 

 the endothelium, are situated. 



There are 12 pairs of perfect septa (Pl. XIV, fig. 10); 

 of these li pairs appear to be the principal ones. as they 

 are stronger built, have a more powerful musculosity, and 

 are sterile; besides those thei - e are 4 pairs of imperfect 

 septa. (jf the 6 pairs of principal, perfect septa, there 

 are 2 pairs of directive septa that correspond to the gonidial- 

 grooves and are very broad. The septa of each pair stand 

 far apart from each other, so that the intraseptal space 

 becomes verv broad (Pl. XIV. fig. 10 R). The longitudinal 

 muscles are secured on the outer surface of each septum. 

 face towards the interseptal space. are verv fally developed. 

 and in proximity to the æsophagus, where they att ai n the 

 greatest thickness, form large frutici which extend far into 

 the interseptal space (Pl. XIV. fig. 1<» fl). The transversal 



