128 



ufuldstændige Septa ere saa lidet udviklede, at de rage 

 si mi tynde Lister kun et lidet Stykke ind i Gastrovascular- 

 hulheden og staa temmelig langt fra de fuldstændige Septa, 

 — og endelig er Muskelanordningen omtrent saaledes som 

 angivet for Mardoll, og neppe som Hertwig og Erdmann 

 angiver for de af dem beskrevne Arter. 



Macrosepta beståa af en Bindevævslamelle (Stutzmem- 

 bran i temmelig smal ved deres Udspring, men som bliver 

 meget bredere, jo længere den kommer op paa Kropsvæg- 

 gen, saa at den indtager den storste Bredde nogle Milli- 

 meter fra Svælgrøret. Tab. XXIV, Fig. 3 c ( ; her spalter 

 Bindevævslamellen sig saa. at der synes at fremkomme en 

 Kanal, Tab. XXIV, Fig. 3 d, paa hvis Vægge jeg dog 

 ikke har kunnet iagttage noget Epithel ; heller ikke findes 

 en saadan Spaltning af Bindevævsmembranen paa alle Septa. 

 Erdmann har hos flerr af hans Arter fundet en saadan 

 Kanal; men den har altid været beklædt med Epithel; jeg 

 tor saaledes ikke med Sikkerhed paastaa, at der er en 

 virkelig Kanal i de fuldstændige Septa hos Epizoanthus 

 arborescens, -- det kan nemlig hænde, at den paa Tver- 

 snittet fremstillede Spalte er en Tilfældighed. 



Som sædvanligt ere Septaerne forsynede med Tver- 

 og Længdemuskler ; Tvermusklerne ere visselig lidet udvik- 

 lede og ganske skjulte af Længdemusklerne, der synes at 

 beklæde begge Sider og ere ingenlunde meget fremtrædende. 

 Det er derfor ikke muligt hos denne Art at kunne be- 

 stemme, hvorvidt Længdemusklerne paa Macrosepta staa i 

 et saadant Forhold til dem paa Microsepta, der skal 

 betinge Pardannelsen. Samtlige Macrosepta keiv Mesen- 

 terialfilamenter og Generationsorganer. 



Mesenterialfilamenterne tåge deres Udspring lidt neden- 

 for Svælgrorets fri Ende, ere ved tyndt Bindevæv bundne 

 til Septumets Bindevævslamel og følger Septumet et langt 

 Stykke ned i Gastrovascularhulheden, men frembyder for- 

 øvrigt intet Særegent i sin Bygning, Tab. XXIV, Fig. 4 a. 

 Generationsorganet, som hos de undersogte Individer bestod 

 af et cylindrisk Ror, der slyngede sig proptrækkerformigt 

 nedover langs Mesenterialfilamentet. var fyldt med Æg, som 

 vare kun lidet udviklede, Tab. XXIV, Fig. 4 b. Kjønnet 

 synes at være adskilt, Paa Tversnit sees saavel Mesente- 

 rialfilamenterne som Kjonsorganerne at være stærkt sam- 

 menrullede paa Septa, hvorved disse faa Udseende af et 

 stilket Blomkaalshoved, Tab. XXIV. Fig. 4; men denne 

 stærke Sammentrækning er sandsynligvis Virkningen af 

 Alkohol, hvori Dyrene have været opbevarede. 



Microsepta. danne yderst smale, listeformige Frem- 

 spring, Tab. XXIV. Fig. 3 e. der ere omtrent lige brede 

 fra deres Begyndelse og til de fæste sig paa Mundskivens 

 Underflade — kan hænde, at de blive lidt bredere opimod 

 denne. Ogsaa her forekommer det mig. at Længdemusk- 

 lerne beklæde begge Sider af Septum og dække Tvermusk- 

 lerne; men hverken det ene eller andet Slags Muskler ere 



imperfect septa are so little developed, that they penetrate, 

 like thin fillets, only a little way into the gastro-vascular 

 cavity, and stand at a considerable distance from the per- 

 fect septa; and. finally, the muscular arrangement is nearly 

 the same as that indicated for Mardoll. and is scarcely 

 like \vhat Hertwig and Erdmann have stated for the 

 species described by them. 



The macrosepta consist of a connective-tissue lamella. 

 (stiitzmembran) råtner narrow at their origin. but this 

 becomes much broader the farther up the body-wall it 

 proceeds, so that it attains its greatest breadth a few 

 millimetres from the æsophagus (Pl. XXIV. fig. 3 c). The 

 connective-tissue lamella becomes here split up. in such a 

 manner, that it appears to produce a channel (Pl. XXIV. 

 fig. 3 d). on whose walls I have. however, not been able 

 to observe any epithelium, and neither is such a splitting 

 of the connective-tissue membrane found on all the septa. 

 Erdmann has found. in several of his species, a similar 

 channel, but it has always been clothed with epithelium. 

 I dåre not, therefore. with certainty. aftirm that there 

 is a real channel in the perfect septa of Epizoanthus 

 arborescens; it may, perhaps, be the case that tbe fissure 

 presented in the section is accidental. 



Tlie septa are. as usual, furnished with transversal 

 and longitudinal muscles; the transversal muscles are 

 evidently little developed, and are quité concealed by the 

 longitudinal muscles. which appear to clothe both sides 

 and are by no means very prominent. It is. therefore, not 

 possible in this species to determine whether the longi- 

 tudinal muscles of the macrosepta stand in such a relation 

 to tlmse of the microsepta. that they occasion the forma- 

 tion of pairs. All the macrosepta carry mesenterial fila- 

 ments and reproductive organs. 



The mesenterial filaments have their origin a little 

 below the free extreinity of the æsophagus, and are at- 

 tached by a thin connective-tissue to the connective-tissue 

 lamella of the septum, and accompany it a long way down 

 into the gastro-vascular cavity. but present, otherwise, 

 nothing peculiar in their structure (Pl. XXIV. fig. 4 a). 

 The organ of reproduetion. which, in the specimens examined. 

 consisted of a cylindrical tube that twiried itself, spirally. 

 like a cork-screw, down along the mesenterial filament, 

 was filled with ova that were only little developed (Pl. 

 XXIV, fig. 4 6). The sexes appear to be separated. In 

 transversal sections, both the mesenterial filaments and the 

 reproductive organs appear to be strongly coiled together 

 upon the septa. so that these last acquire the appearance 

 of a cauliflower head seated on a stalk (Pi. XXIV, fig. 4); 

 but that great contraction is probably due to the action 

 of the alcohol in which the animals have been preserved. 



The microsepta form extremely narrow fillet-formed 

 protuberances (Pl. XXIV. fig. 3 e), which are nearly uniform 

 in breadth from their commencement until they attacli 

 themselves to the under surface of the oral disc; they are 

 perhaps very slightly broader close up to it. Here also, 

 it appears. to me, that the longitudinal muscles cloth both 

 sides of the septum, and cover the transversal muscles. but 



