112 



laget, der hos de fleste af de Arter, vi have undersøgt, 

 bestaar af større og mindre polyedriske Celler, — ja hos 

 enkelte, som f. Ex. Sipunculus priapuloides, opnaa disse 

 Celler en betydelig Størrelse, ere forsynede med Kjerner 

 og et rigt, kornet Protoplasma-Indhold (Tab. 13, Fig. 9 h, h). 

 Dette Epithel hviler paa en Slags Basalmembran, der be- 

 staar af et fint Bindevæv. Hos vore Sipunculider, der 

 alle ere temmelig smaa, har det ikke lykkedes os at 

 separere denne Basalmembran fra Epithellaget, hvorved 

 en særskilt Hud (Cutis) kunde fremkomme; men fra den 

 underste Flade af Basalmembranen have vi fundet en 

 Membran udgaa, der forlænger sig imellem baade Ring- 

 og Længdemusklerne og gaar over i den Hinde (Perito- 

 neum), der beklæder Kropshulheden, og som vi senere 

 komme til at omtale. Vi have ikke fundet at Basalmem- 

 branen (Cutis) har et saadant krydsformigt, stribet Ud- 

 seende, som Keferstein angiver at være Tilfældet hos Phas- 

 colosoma Antillarum og Puntarenæ. Graber benægter lige- 

 frem Tilstedeværelsen af denne krydsformige Stribning. 



De i Hudeu hos Sipunculiderne indleirede Hudlege- 

 mer have vistnok hos alle de Arter, vi have havt Anled- 

 ning til at undersøge, en forsaavidt overensstemmende 

 Character, som de indeslutte en C elle an samlin g og ud- 

 munde gjennem Cuticula; men de frembyde dog betyde- 

 lige individuelle Forskjelligheder, hvilke vi nu skulle frem- 

 hæve. Hos vore to Sipunculus-Arter ligge de meget løse 

 under Epithellaget og altid omgivne af en tynd Kapsel 

 (Tab. 13, Fig. 9 c, b). Deres Indhold bestaar dels af et 

 større Antal mindre Celler (Fig. 9 b), dels kun af to store 

 mod hinanden fladtrykte, halvkugleformige Celler, der hver 

 er forsynet med en stor Vacuole (Fig. 9 c). Hos Slæg- 

 terne Phascolosoma, Onchnesoma og Tylosoma ligge Hud- 

 legemerne enten, saaledes som Tilfældet er hos Ph. squa- 

 matum, aflangt fladtrykte mellem Matrix (Hypodermen) 

 og Ringmusklerne med en lang Udførselskanal (Tab. 14, 

 Fig. 15 a, b), eller de ligge ligesom indkrængede (indkap- 

 slede) i Cuticula, som hos Ph. Lovénii (Tab. 14, Fig 21), 

 og tildels hos Ph. Strombi — nemlig de Hudlegemer, som 

 hos denne Art danne Prominentser af Huden og ere om- 

 givne af en hesteskoformig Cuticularfortykkelse, saaledes 

 som af Keferstein 1 ) beskrevet. Hos Ph. vulgare ligge 

 Hudlegemerne kun for endel indi Cuticula; de have en 

 Kegleform, men Keglens Basis hviler lige paa Ringmusk- 

 lerne, og her ere de tydelig omgivne af en Kapsel, der 

 dannes af Basalmembranen. De hos Ph. Lovénii i Cuti- 

 cula indkapslede Hudlegemer synes derimod ikke at være 

 omgivne af en saadan Kapsel. De ere bugede, næsten 

 krukkeformige (Fig. 21) med en smal Grunddel, hvor- 

 igjennem sees tydeligt, at Epithellaget gaar ind og be- 

 klæder hele Fladen af den Kapsel, der er dannet af 

 Cuticula (Fig. 21 a, a) og hvori Hudlegemets mægtige 

 cylindriske, opad noget tilspidsede Celler ligge frit (Fig. 

 21 d). Hos Ph, squamatum og Onchnesoma Steenstrupii 

 ere disse Celler hverken saa store eller cylindriske som 



2 ) Zeitschrift f. w. Zoologie 15 B. 1865, Fag. 406, Tab. XXXIII, 

 Fig. 35 og Pag. 431. 



lies the epithelial layer, which, in most of the species 

 we have examined, consists of larger and smaller poly- 

 hedral cells; nay in some — as for instance Sipunculus 

 priapuloides, — these cells attain a considerable size 

 contain nuclei and a rich granulated protoplasma (Tab. 13 

 fig. 9 h, h). This epithelium rests on a sort of basal 

 membrane, which consists of a fine connecting tissue. In 

 our Sipunculidæ, which are all rather small, we have not 

 been able to separate this basal membrane from the 

 epithelial layer, so as to produce a separate skin (cutis)- 

 but we have found that, from the under surface of the 

 basal menbrane, there issues a membrane which extends 

 both among the annular and longitudinal muscles, and 

 goes over into the membrane (peritoneum) that lines the 

 perivisceral cavity, and which we shall mention hereafter. 

 We have not found that the basal membrane (cutis) has 

 such a cross-striped appearance as Keferstein states is 

 seen in Phascolosoma Antillarum and Puntarenæ. Graber 

 denies absolutely the existence of this cross-striping. 



The cuticular bodies (Hautkörper) imbedded in the 

 skin of the Sipunculidæ, have certainly, in all the species 

 we have had occasion to examine, a so far similar cha- 

 racter, as they include a collection of cells, and have 

 their exeretory-orifice through the cuticle; but they yet 

 exhibit important individual differences, which we shall 

 now specify. In our two species of Sipunculus, they lie 

 very loose under the epithelial layer, and are always 

 surrounded by a thin capsule (Tab. 13, ß.g. 9 c, b). Their 

 contents consist partly of a larger number of smaller 

 cells (fig. 9 b), partly only of two large semi-globular 

 cells, flattened against each other and having each a large 

 vacuole (fig. 9 c). In the genera Phascolosoma, Onchne- 

 soma and Tylosoma, the cuticular bodies either lie, as 

 in the Ph. squamatum, flattened oblong between the 

 matrix (Hypodermis) and the annular muscles, with a long 

 eductive canal (Tab. 14, üg. 15 a, b), or they lie, as it 

 were, invaginated (incapsulated) in the cuticle, as in Ph, 

 Lovénii (Tab. 14, fig. 21), or sometimes in Ph. Strombi; 

 namely the cuticular bodies which in the latter species 

 form prominences in the skin, and are surrounded by a 

 cuticular enlargement in the form of a horse-shoe, as 

 described by Keferstein 1 ). In Ph. vulgare, the cuticular 

 bodies only lie partly within the cuticle; they have a 

 conical form; but the base of the cone rests directly on 

 the annular muscles; and here they are evidently sur- 

 rounded by a capsule formed of the basal membrane. 

 The incapsulated cuticular bodies in the skin (Cuticula) 

 of the Ph, Lovénii seem, on the other hand, not to be 

 enveloped in such a manner. They are bellied so as to 

 be nearly pot-shaped (fig. 21) with a narrow base, through 

 which it may distinctly be seen that the epithelial layer 

 goes in and lines the whole surface of the capsule, which 

 is formed of the cuticle (fig. 21 a, a) and wherein the 

 strong cylindrical cells (above somewhat tapered) of the 



*) Zeitschrift f. w. Zoologi, 15 Vol. 1865, p. 406, Tab. XXXIII; 

 fig. 35 and p. 431. 



