76 



placerede paa den ydre Plade af hvert Septum og vende 

 mod det interseptale Runi, imedens de transverselle Muskler 

 (hekke næsten ganske den indre Flade og vende altsaa mod 

 det vide. intraseptale Rum. De øvrige -i Par principale 

 Septa. nemlig 2 paa hver Side af Retningssepta, have 

 Muskulaturen placeret ganske modsat, saaledes at de longi- 

 tudinelle Muskler ere paa den indre, og de transverselle 

 paa den ydre Flade. Tab. XV. Fig. 3 a. De longitudi- 

 nelle Muskler ere henimod Svælget stærkest udviklede, hvor 

 de forme sig i Buske, idet der fra Skillevaggen (Septum) 

 udgaa listefbrmige Bindevævsforlængelser, hvorpaa Musk- 

 lerne heste sig. De andre li Par fuldstændige Septa maa 

 vel ansees som sekundære, Tab. XV, Fig. 3 h ■ de ere 

 stillede saaledes, at imellem hvert 2 Par principale Septa, 

 altsaa i det principale Kammer, er 1 Par af de fuldstæn- 

 dige. sekundære Septa. Paa disse ere Længdemusklerne 

 fæstede paa den indre Flade, vende mod hverandre i det 

 intraseptale Paun, imedens Tvermusklerne dække Største- 

 delen af den ydre Flade i det interseptale Kum. Alle de 

 fuldstændige Septa bære Mesenterialfilamenter; men imedens 

 de 6 Par principale Septa ere golde, sees paa enkelte af 

 de sekundære Septa Acontier. 



Imellem hver 2 Par af samtlige fuldstændige Septa 

 er der 1 Par ufuldstændige, der indtager knapt den halve 

 Længde af det interseptale Kum. saa at dettes anden Halv- 

 del, som vender mod Svælgrøret. er frit, Tal». XV. Fig. .'! r. 

 Disse ufuldstændige, tertiære Septa ere ligesom de fuld- 

 stændige forsynede med Længde- og Tvermuskler; de bære 

 baade Acontier og Generationsorganer, og det i saa stor 

 Mængde, at disse Organer udfylde en stor Del af det inter- 

 septale Kum, hvori de rindes. Åcontierne sidde øverst, 

 Tal). XV, Fig. 3 d, og afvige ikke i Organisation fra de 

 tidligere omtalte Acontier, men synes at være i større 

 Mængde tilstede, end hos nogen af de forhen omtalte 

 Phellia-arter. Nedenfor Åcontierne, imod Gastralhulhedens 

 Bund, sidde Kjonsorganerne. der danne lange,. baandformige, 

 sammenrullede Ovarier, Tab. XV, Fig. 3 c. hvori sees .li 

 i forskjellige Utviklingsstadier. Svælgrøret er temmelig 

 langt, og paa dets indre Flade forsynet med to temmeligi 

 brede Svælggruber, hvis Epithel bestaar af lange Cylinder- 

 celler. dei' bære lange Cilier; den øvrige Del af Svælgfladen 

 har stærke Længdefolder, beklædte med Cylinderceller, men 

 hvis Cilier ere meget kortere. Imellem (Jylindercellerne 

 sees mange encellede Slimkjertler; men i Svælggruberne 

 tindes ingen saadanne paa det undersøgte Exemplar. 



De b' Par fuldstændige, principale Septa tåge deres 

 Begvndelse fra Centrum af Fodskivens indvendige Flade; 

 de andre ti Par fuldstændige Septa udspringe lidt udenfor 

 Oentrum og de 12 Par ufuldstændige Septa omtrent midt 

 imellem Centrum og Peripherien. 



whilst, also, the longitudinal muscles are placed on the 

 outer surface of each septum and face towards the inter- 

 septal space, whilst the transversal muscles almost entirely 

 cover the inner surface and consequently face towards the 

 wide intraseptal space. The other 4 pairs of principal 

 septa. viz. 2 upon each side of the directive septa. have 

 tlu ir musculosity placed in quite a reverse manner: tims. 

 the longitudinal muscles are upon the inner, and the trans- 

 versal muscles upon the outer surface (Pl. XV. fig. 3 a). 

 The longitudinal muscles are most developed in the neigh- 

 bourhood of the gullet, where they form themselves into 

 frutiei. owing to fillet-formed connective-tissue prolongations 

 upon which the muscles attach themselves issuing from the 

 divisional wall (septum). The other 6 pairs of perfect septa 

 must. I suppose, be considered as secondary septa (Pl. XV. 

 fig. 3 &); they are placed in such manner that between each 

 2 pairs of principal septa. consequently in the principal 

 chamber, there is 1 pair of perfect, secondary septa. Upon 

 these the longitudinal muscles are secured on the inner sur- 

 face. face towards each other in the intraseptal space. whilst 

 the transversal muscles cover the greater part of the outer 

 surface in the interseptal space. All the perfect septa 

 carry mesenterial filaments; hut whilst the 6 pairs of prin- 

 cipal septa are sterile, acontia are observed upon some of 

 the secondary septa. 



Between every two pairs of all the perfect septa, 

 there is 1 pair of imperfed septa. which occupy barelj 

 half the length of the interseptal space, so that its remaining 

 half. which faces towards the æsophagus, is free (Pl. XV. 

 fig. 3 c). These imperfect, tertiary septa are. like the perfect 

 septa. furnished with longitudinal and transversal muscles; 

 they carry both acontia and reproductive organs, and in 

 such great abundance that these organs fill up a greal part 

 of the interseptal space in which they are found. The 

 acontia are placed uppermost (Pl. XV. fig. 3 il), and do 

 not differ in organisation from the acontia previously spoken 

 of, lint appear to be present in greater abundance than 

 in any of the species of Phellia previously mentioned. 

 Below tlie acontia. towards the bottom of the gastra] cavity. 

 the reproductive organs are situated, forming loug ribbon- 

 like coiled ovaries (Pl. XV, fig. 3 e), in which ova in 

 various staves of development are observed. The æsophagus 

 is rather long and is. upon its inner surface. furnished with 

 two rather broad gullet-grooves whose epithelhun consists 

 of long cylinder-cells carrying long ciliæ. The remaining 

 part of the gullet surface has strong longitudinal folds 

 clad with cylinder-cells. hut whose ciliæ are much shorter. 

 Between the cylinder-cells numerous unicellular mucous 

 glands are seen. but in the gullet-grooves no such glands 

 were found in the specimen examined. 



The (3 pairs of perfect, principal septa originate in 

 the centre of the inner surface of the pedal disc; the other 

 li pairs of perfect septa originate a littte beyond the centre. 

 and the 12 pairs of imperfect septa originate about half 

 way between the centre and the periphery. 



