147 



Samtlige Septa bære Mesenterialfilamenter og Genera- 

 tionsorganer, Tab. XVII. Fig. 1. De tåge deres Udspring 

 lige ved Spiserørets øverste Del, strax under Mundskiven, 

 og ere fæstede paa den ene FlaMe af Septurn, imellem 

 Muskelfibrene, ved en membranøs Forlængelse af Septumets 

 Bindevæv. Septumerne have ikke hor som ellers hos 

 Actiniderne en fri Rand, hvortil de nævnte Organer ere 

 bundne; thi. som man erindrer, er hos Fenja intet Gastro- 

 vasculariura, hvori Skillevæggene kunne hænge frit; tvertimod 

 ere de overalt fæstede udåd til Kropsvæggen og indad til 

 Spiserør og Tarmkanal. Mesenterialfilamenterne ere place- 

 rede nærmest Spiserøret og strække sig proptrækkerforniigt 

 bagover (nedover) til omtrent Midten af Reetum uden at 

 være bundne til denne. Tab. XVII, Fig. 1 b; deres Byg- 

 ning afvige ikke fra den sædvanlige. 



Generationsorganerne ligge udenfor Mesenterialfila- 

 menterne og ere ligeledes bundne til Septum ved en Binde- 

 vævsforlængelse, der er beklædt med Endothel, Tab. XVII. 

 Fig. 8, 9, 10 a. Æggestokkene danne baandformige, noget 

 fladtrykte Rør, som slynge sig nedover Septum. lige fra 

 Mundskiven og langt længere end Mesenterialfilamenterne. 

 Tal). XVII, Fig. 8 b. Jeg har saaledes paa et Exemplar 

 seet Æggestokke paa et Par Septa ende i Nærheden af 

 Kropsnulhedens Bund. Disse Rør ere indvendig beklædte 

 med et Epithel, bestaaende af store, runde Celler med 

 Kjerne og Kjernelegeme, og her sees Æggeue i forskjel- 

 lige Udviklingsstadier at ligge i Almindelighed to sammen, 

 Tab. XVII, Fig. 1 r. 10 6. 



Testiklerne ligge yderst, 



Tab. XVII, Fig. 1 d, 8 f, 

 saaledes at Æggestokkene ligge imellem disse og Mesen- 

 terialfilamenterne. De tåge deres Udspring lige ved Ova- 

 riernes. men strække sig længere bagtil end disse. De 

 eie ligesom Æggestokkene fæstede til Septum ved en 

 Forlængelse af dettes Bindevæv, Tab. XVII, Fig. 9 a, og 

 beståa af to slyngeformede. næsten runde Bor, der udven- 

 digt ere beklædte med cylinderforniede Endothelceller, som 

 ogsaa beklæde Mesenteriet, og imellem hvilke sees en 

 Mængde Nematocyster; indvendigt ere de tapetserede med 

 Epithel, der dannes af store, runde Celler med en rund. 

 excentrisk Kjerne, hvori et rundt Kjernelegeme. Tab. XVII, 

 Fig. 9 b. Mange af disse Celler ere fyldte med runde, 

 glinsende Legemer (uudviklede Spermatozoer), Tab. XVII, 

 Fig. 9 c, andre ere saagodtsom tomme, men udenfor dem 

 sees store Hobe med lignende, glinsende Legemer som 

 de, der tindes indeni Celleme. Tab. XVII. Fig. 9 d. 

 Blandt disse Hobe sees mange af de runde, glinsende 

 Legemer at være forsynede med en kort Hale (mere ud- 

 viklede Spermatozoer), Tab. XVII. Fig. 9 e. Det ser her 

 nd, som om Spermatogenesen foregaar at Spermatoblaster- 



whether there is an intermediate laver, a ventral layer, 

 (Peritoneum) to which they are attached, in the manner 

 that will snbsequently be shown to be the case with the 

 cesophagus and the intestinal jcanal, eau not be here 

 determined. 



All the septa. carry mesenterial filaments and repro- 

 ductive organs (Pl. XVII, fig. 1). These have their 

 origin exactly at the uppermost part of the gullet-tuhe, 

 just below the oral disc, and are secured to the one sur- 

 face of the septum. between the mnscle-fibres, by a mem- 

 branous prolongation of the connective-tissue of the septum. 

 The septa have not heri', as usually is the case with 

 Actinida, a free margin to which the organs named are 

 attached; it will be remembered that there is in Fenja no 

 gastro-vascular cavity in which the septa could freely hang; 

 on the contrary they are everywhere secured, exteriorly, to 

 the body-wall, and, interiorly, to the gullet-tube and the 

 intestinal canal. The mesenterial filaments are placed 

 next to the gullet-tube, and extend themselves spirally, 

 backwards (downwards), to nearly the middle of the reetum 

 without, howeyer, being secured to it (Pl. XVII, fig. 1 b). 

 Their structure presents no divergence from the common. 



The lepmductive organs are situated outside the 

 mesenterial filaments, and are also secured to the septum 

 by a connective-tissue prolongation, which is clad with 

 endothelium (Pl. XVII, Bgs. 8. 9. 10 a). The ovaries 

 form ribbon-shaped, somewhat adpressed tubes which twine 

 themselves down along the septum, quite from the oral 

 disc and mueh farther than the mesenterial filaments (Pl. 

 XVII, fig. 8 b). I have seen. indeed, in one specimen, 

 the ovary on a couple of septa terminate in proximity 

 to the bottom of the body-cavity. These tubes are clad 

 internallv with an epithelium consisting of large, round 

 cells with nucleus and nucleolus, and here the ova are 

 seen in various stages of development, usually lying two 

 together (Pl. XVII. fig. 1 c, 10 b). 



The testicles lie outermost (Pl. XVII, fig. 1 <l 8 <■). 

 so that the ovaries are situated between them and the 

 mesenterial filaments. They have their origin exactly at the 

 same point as the ovaries, but extend themselves farther 

 backwards than the latter do. They are, like the ovaries, 

 secured to the septum by a prolongation of its connec- 

 tive-tissue (Pl. XVII, fig. 9 a), and consist of two spiri- 

 form. almost rcrind tubes, clad externally with cylind- 

 rical endothelial cells, which also cloth the mesentery, 

 and between which a multitude of nematocysts are visible. 

 Internally, they are coated with epithelium formed of large 

 round cells with a round excentric nucleus in which there 

 is a round corpuscle (Pl. XVII. fig. 9 b). Many ofthose 

 cells are occupied by round shining bodies (undeveloped 

 spermatozoa) (Pl. XVII, fig. 9 c). Others are almost per- 

 fectly empty. but outside them there are seen great crowds 

 of shining bodies, similar to those found in the cells (Pl. 

 XVII, fig. 9 d). Among those crowds, many of the round 

 shining bodies are seen to be furnished with a short tail 

 (more perfectly developed spermatozoa) (Pl. XVII. fig. 9 e). 

 It appears. here. as it the spermatogenesis proceeds from 



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