142 



Ribberne sees en yderst smal Fure, Fig. 2, d. 3, a, der 

 udvider sig noget opimod Tentakelranden og danner lier 

 et langagtigt, trekantet Rum, der er nøgent til Siderne, men 

 i hvis Midte er en Længdestribe af Spilder, Fig. 3, b. Ten- 

 taklerne ere 2.5""" lange, tykke ved Granden og paa deres 

 aborale Side vel bepantsrede med Spikier ; ogsaa Pinnulerne 

 ere forsynede med saadanne. 



Anatomisk-histologisk Undersøgelse. 



Hele Zoanthodemet er beklædt med et Ectoderm, der 

 bestaar af polyædriske Celler med en temmelig stor, næsten 

 rund, lidt excentrisk liggende Kjerne med sit Kjernelegeme, 

 og omgiven af et fintkornet, halv gjennemsigtigt Proto- 

 plasme. Indenfor Ectodermet er et hyalint Bindevævslag, 

 fra hvis ydre Flade udgaar en Mangfoldighed af fine Ud- 

 løbere, der danne et Net, hvis Masker ere beklædte med 

 Ectodermceller og optagne af Spikier, saaledes at i hver 

 Maske ligger en Spikel, Fig. 4, a. Fra dette Bindevævs 

 indre Flade udgaa Forlængelser imellem Cellerne og danne 

 her et smalt Coenenchym, hvori ikke alene sees Bindevævs- 

 legemer og Ernæringskanaler med- deres Epithel, men ogsaa 

 Spikelafieiringer, Fig. 4, b. 



Paa Polypcellernes indre Væg sees de 8 Septula at 

 strække sig ned til Cellens Bund ; paa de 6 af dem iagt- 

 tages Kjønsorganerne, der beståa som sædvanligt af stilkede 

 Kapsler, hvori sees Æg i forskjellige Udviklingsstadier, 

 Fig. 4, c. 



Polypernes ydre Beklædning adskiller sig fra den 

 øvrige Del af Zoanthodemet kun derved, at Ectodermet har 

 to Lag polyædriske Celler, og at disse synes at være rigere 

 paa Protoplasmaindhold, Fig. 5, a. Indenfor Ectodermet ei- 

 et lignende Bindevæv med sit Maskenet; Maskerne ere her 

 større, Fig. 5, c. Ectodermcellerne, der beklæde Maske- 

 væggene, ere tydeligere, Fig. 5, b, og det seer ud, som om 

 der i nogle Masker ligge flere Spikler sammen. Fra den 

 indvendige Flade af Bindevævet udgaa de 8 Septa, som 

 fæste sig paa Svælgrørets ydre Side og ere forsynede med 

 Tver- og Længdemuskler, samt beklædte med et Lag runde, 

 temmelig klare Endothelceller, der ogsaa give Svælgrøret 

 sin ydre Beklædning, Fig. 5, d. 



Svælgrøret har 8 tæt liggende Spikelrækker, Fig. 6, c, 

 dog saaledes ordnede, at 4 Rækker ligge paa hver Side af 

 Bugfladen, som er spikelfri, Fig. 6, b. Paa Svælgets indre 

 Væg, langs Bugsiden, sees en halvrund, temmelig dyb Grube 

 (Svælggruben), der er beklædt med lange Pidskeceller, Fig. 

 5, e; den øvrige Del af Svælget er beklædt med kortere 

 Celler med temmelig korte Cilier. Imellem disse Celler sees 

 hist og her isolerede, pæreformige, encellede Slimkjertler 



body bas 8 ribs on which the spicules are placed longi- 

 tudinally; between the ribs, an extremely minute furrow 

 is seen (fig. 2, d, 3, a), which becomes somewhat dilated 

 in the proximity of the tentacular margin, and forms, there, 

 an elongate triangular space which is bare at the sides, 

 but in whose middle there is a longitudinal stripe of spicules 

 (fig. 3, b). The tentacles measure 2.5™'" in length at the 

 base; on their aboral side they are well sheathed with spi- 

 cules; the pinnules are also furnished with spicules. 



Anatomo-histological Examination. 



The entire Zoanthodem is clad with an ectoderm, 

 which consists of polyhedrical cells containing a pretty 

 large, almost globular, somewhat eccentrically placed, nucleus 

 and nucleus-corpuscle, surrounded by a minutely gran- 

 ular, semi-transparent protoplasm. Inside of the ectoderm 

 there is a hyaline connective-tissue layer, from whose outer 

 surface a multitude of prolongations issue forming a reti- 

 culation whose meshes are clad with ectoderm-cells, and are 

 occupied by spicules in such a manner, that one spicule is 

 situated in each mesh (fig. 4, a). From the inner surface 

 of this connective-tissue prolongations issue between the 

 cells, and form here a narrow sarcosoma, in which are 

 observed, not only connective-tissue corpuscles and nutritory 

 ducts with their epithelium, but also spicular deposits 

 (fig. 4, b). 



On the inner wall of the polyp-cells, 8 septula are 

 observed to extend down to the bottom of the cell; on 6 

 of these the reproductive organs are seen, consisting, as 

 usual, of pedunculated capsules in which ova in various 

 stages of development are observed (fig. 4, c). 



The outer covering of the polyps is distinguished trom 

 the rest of the Zoanthodem, only by the fact that the ecto- 

 derm has two layers of polyhedrical cells, and that these 

 appear to be richer in protoplasmic substance (fig. 5, a). 

 Inside of the ectoderm there is a similar connective-tissue 

 with its reticulation; in this the meshes are larger (fig. 5, c), 

 the ectoderm-cells which clothe the walls of the meshes are 

 more distinct (fig. 5, b), and it appears as if in several "meshes 

 numerous spicules lie together. From the inner surface ot 

 the connective-tissue issue the 8 septa which attach them- 

 selves to the outer side of the gullet-tube, and these are 

 furnished with transversal and longitudinal muscles, and are 

 clad with a layer of globular, pretty pellucid, endothelial 

 cells which also serve as the outer covering of the gullet- 

 tube (fig. 5, d). 



The gullet-tube has 8, closely placed, spicular series 

 (fig. 6, a) arranged, however, in such a manner, that 4 

 series lie on each side of the ventral surface, which is devoid 

 of spicules (fig. 6, b). On the inner wall ot the gullet, 

 along the ventral side, a semi-circular^ rather deep, groove, 

 (the gullet-groove) is observed, which is clad with long 

 flagelhform cells (fig. 5, e). The remaining part of the 

 gullet is clad with shorter cells which have rather short 



