131 



stændige og fæste sig paa Svælgrøret, ere ikke meget brede 

 og have Længde- og Tvermuskler, der ikke ere synderlig 

 udviklede. Længdemuskleme indtage Støi^stedelen af Sep- 

 tumets ene Side og ere fjærformede; fra den anden Side, 

 hvor Tvermusklerne ere festede, udgaa yderst smale 

 Bindevævsmembraner, som bære Mesenterialfilamenterne og 

 Generationsorganerne, Tab. XXIV. Fig. 8 a; Tab. XXV, 

 Fig. 1 c. Mesenterialfilamenterne frembyde intet Særegent: 

 de udspringe lige ved den nederste, fri Ende af Svælgrøret, 

 ligge inderst mod Kropsvæggen og strække sig ned mnd 

 Gastrovaseularhulhedens Bund. 



Generationsorganerne udgaa omtrent fra samme Sted 

 som Mesenterialfilamenterne, kun lidt nedenfor disse og 

 Huge udenfor dem. altsaa fjernere Kropsvæggen. Kjønnet 

 er sandsynligvis adskilt. Paa de undersøgte Individer iagt- 

 toges kun Æggestokke; disse slyngede sig proptrækker- 

 formet nedover Septum og indeholdt Æg i forskjellige 

 Udviklingsstadier, men som oftest var kun 1 Æg fuldt ud- 

 viklet. og dette laa da iudeni en temmelig rummelig Kapsel, 

 Tab. XXV. Fig 1 d. 



Af de 18 fuldstændige Septa er der to Retningssepta, 

 som ere festede til Svælgrørets ydre Side just der, hvor 

 Svælggruben findes ])aa dettes indre Flade, Tab. XXIV, 

 Fig. 8 b. Paa disse Septa er Muskelanordningen saaledes, 

 som Dr. Erdmann har fundet den hos de af ham beskrevne 

 Arter; de longitudinelle Muskler ere festede paa Sep- 

 tumets ydre Side og vende fra hverandre, imedens de 

 transverselle tindes paa den indre Side og saaledes vende 

 mod hverandre; saavidt mine Undersøgelser gaa. er dette 

 ogsaa Tilfældet med de øvrige Septa. 



Microsepta ere ligeledes 18, livoraf 2, der ere festede 

 til Rygsiden, ere Retningssepta og .have Musklerne placerede 

 som paa de fuldstændige Retningssepta. Tab. XXIV. Fig. 

 8 c. Disse ufuldstændige Septa, der ere golde, ere meget 

 smale, listefopmige og placerede imellem de fuldstændige 

 Septa, Tab. XXIV, Fig. 8 cl. De ere dannede ligesom 

 Macrosepta af en tynd Bindevævsmembran , hvis begge 

 Sider ere beklædte med Muskler saaledes, at paa den ene 

 Side ere Længdemuskleme festede og paa den anden Tver- 

 musklerne. Her synes Musklerne. som i det Hele tåget 

 kun ere lidet udviklede. at være ordnede saaledes. at Længde- 

 muskleme vende mod Længdemuskleme, og Tvermusklerne 

 mod Tvermusklerne paa Macrosepta. Herfra gjor dog 

 Retningssepta en Undtagelse, hvilket ovenfor er antvdet. 

 Jeg indrømmer, at hos denne Art er der stærkere Grund 

 end hos de to tidligere beskrevne Arter til at parre Jlacro- 

 og Microsepta sammen. Samtlige Septa ere beklædte med 

 et Endothel. bestaaende af cilierende Cylindereeller. der 

 egentlig beklæde hele Gastrovascularhulheden. 



macrosepta, which are perfect and attach themselves to 

 the æsophagus, are not very Innad, and have longitudinal 

 and transversal muscles that are. however, not particularlj 

 well developed. The longitudinal muscles occupy the 

 greater part of the one side of the septum and are 

 feather-shaped ; from the other side. where the trans- 

 versal muscles are secured, extremely narrow connective- 

 tissue membranes issue, bearing the mesenterial fila- 

 ments and reproductive organs (Pl. XXIV. fig. 8 a : 

 Pl. XXV. fig. 1 c). The mesenterial filaments present 

 nothing peculiar; they issne dose to the lowest free 

 extremity of the æsophagus, lie next to the body-wall, 

 and extend themselves down towards the bottom of the 

 gastro-vascular cavity. 



The organs of reproduction issne from about the 

 same situation as the mesenterial filaments. hut a little 

 beiow them and lving outside, consequently farther from 

 the body-wall. The sexes are most probably separated. 

 In the individuals examined, ovaries only were observed; 

 those twined themselves spirally, like a cork-screw. down 

 the seilturn, and contained ova in various stages of develop- 

 ment, lint most frequently one ovum only was tully devel- 

 oped. and that one then lav inside a pretty roomy capsule 

 (Pl. XXV. fig. 1 cl). 



Of the 18 perfect septa, there are 2 directive septa 

 which are secured to the outer side of the æsophagus. 

 just at the point where the gullet-groove is found upon 

 its inner surface (Pl. XXIV. fig. 8 h\. Upon these septa 

 the muscular arrangement is like what Dr. Erdmann has 

 found it to be in the species described by hiin ; the longi- 

 tudinal muscles are secured to the outer side of the septum 

 and turn away from each other. whilst the transversal 

 muscles are found upon the inner side, and consequently 

 face towards each other; so far as my investigations extend 

 that is also the case with the remaining septa. 



Of microsepta there are likewise 18. of which 2 that 

 are secured to the dorsal side are directive septa and 

 have the muscles placed in same manner as on the perfect 

 directive septa (Pl. XXIV, fig. 8 c). These imperfect septa. 

 which are sterile, are very narrow, fillet-formed, and are 

 placed between the perfect septa (Pl. XXIV. fig. 8 cl). 

 They are formed, like the macrosepta, of a thin connective- 

 tissue membrane, both of whose sides are clad with muscles 

 in such manner, that on the one side longitudinal muscles 

 are attached. and on the other side transversal muscles. 

 Here the muscles. which. upon the whole, are only little 

 developed, appear to be arranged in such manner, that 

 the longitudinal and transversal muscles respectively 

 face towards the longitudinal aud transversal muscles of 

 the macrosepta. From that rule. however. the directive 

 septa form an exception. which has been indicated above. 

 I confess that in this species there is stronger reason 

 than in the previously described species. to pair the macro- 

 septa and the microsepta togethe.r. All the septa are clad 

 with an endothelium consisting of ciliating cylinder-cells, 

 which indeed clothe the entire gastro-vascular cavity. 



17* 



