155 



begge disse Arter ere yngre Individer af Ph. margarita- 

 ceum, S., eller i det høieste Localitets-Varieteter af denne. 

 Under Navnet Ph. pyriforme, Danielss., har Hr. Théel 

 givet en Beskrivelse af en Phascolosoma-Art, der ikke er 

 Danielssens pyriforme; thi denne afviger saa væsentlig fra 

 Phascolosoma, at vi for den have dannet en ny Slægt, 

 nemlig Onchnesoma. Derimod have vi Grund til at an- 

 tage, at Hr. Théels Ph. pyriforme falder sammen med den af 

 Professor Möbius beskrevne og afbildede Ph. procerum. 1 ) 



Endelig skulle vi omtale de af Dr. Théel beskrevne 

 Generationsorganer, der fuldkommen svare til de af os 

 beskrevne traadformige, bugtede Legemer, et ved hver 

 Bugretractors Basaldel, og hvori vi stundom have fundet 

 Æg i forskj eilige Udviklingsstadier. 



Ogsaa Semper har gjort opmærksom paa disse Or- 

 ganer og fremsat den Formodning, at de muligens vare 

 G enitalkj ertier. At disse Legemer ikke ere Æggestokke 

 eller Testikler, ere vi overbeviste om. Vi have paavist 

 hos mange Phascolosoma-Arter Generationsorganerne og 

 henvise forøvrigt dertil; kun skulle vi bemærke, at de 

 traadformige, bugtede Legemer, som Hr. Théel angiver 

 for Kjønsorganer, ofte mangle. Saaledes findes de ikke 

 hos Ph. squamatum, Onchnesoma Steenstrupii og Sarsii, 

 og heller ikke hos Tylosoma. Derimod have vi hos Ph. 

 squamatum fundet Kjønsorganet fæstet til Spiserøret paa 

 samme Maade, som vi have angivet for flere andre Phas- 

 colosoma-Arter. 



Dr. Teuschers Iagttagelser over Sipunculiclerne stemme 

 i de fleste Punkter overens med vore, — kun i et Par 

 ere de temmelig afvigende, nemlig med Hensyn til Hud- 

 legemerne og Generationsorganerne. Dr. Teuscher antager 

 Hudlegemerne for at være Sandseorganer ; heri kunne vi 

 ikke være enige, idet vi have paavist, at de ere slimaf- 

 sondrende Organer. Kjønsorganerne angiver han for Si- 

 punculus's Vedkommende at være de Længdekanaler, som 

 findes i Huden, og som dannes derved, at i den midterste 

 Del af Kropsvæggen er Hudens Bindevævslag sammen- 

 voxet med Ringmusculaturen kun paa de Steder, hvor 

 Længdemusklerne løbe under Ringmusklerne. I disse 

 Længdekanaler har han fundet Æg i forskj eilige Udvik- 

 lingsstadier og mener derfor, at de udvikles der. For 

 Phascolosoma's Vedkommende antager han det for sand- 

 synligt, at Æggene fremstaa af det Epithel, der beklæder 

 Kropshulheden. Saavel med Hensyn til Længdekanalerne 

 som Generationsorganerne have vi tidligere udførligt ud- 

 talt os. 



') Die Expedition zur physikalisch-chemischen und biolo- 

 gischen Untersuchungen der Nordsee im Sommer 1872. Pag. 175, 

 Taf. 3, Fig. 1-5. 



young individuals of Ph, margaritaceum S. or at most 

 local varieties of the same. 



Under the name Ph. pyriforme Danielss., Mr. Théel: 

 has given a description of a sort of Phascolosoma which 

 is not Danielssens pyriforme; for this differs so essentially 

 from the genus Phascolosoma, that we have formed for 

 it a new genus Onchnesoma. But we have reason to 

 suppose, that Mr. Théel's Ph. pyriforme coincides with 

 the Ph. procerum l ) described and delineated by profes- 

 sor Möbius. 



Finally we must notice the organs of generation 

 described by Dr. Théel, which correspond perfectly to 

 those filiform and sinuous bodies described by us, one at 

 the basal part of each ventral retractor, and wherein we 

 have sometimes found ova in different stages of develop- 

 m ent. 



Also Semper has drawn attention to these organs^ 

 and emitted the opinion that they were possibly genital 

 glands. That these bodies are not ovaries nor testicles, 

 we are convinced. We have pointed out the organs of 

 generation in many species of Phascolosoma, and refer there- 

 to; — we shall only remark that the filiform, sinuous 

 bodies, indicated by Mr. Théel as sexual organs, are often 

 wanting. Thus they are not found in Ph. squamatum,, 

 Onchnesoma Steenstrupii and Sarsii, nor in Tylosoma. 

 On the other hand we have found in the Ph. squamatum 

 the sexual organ attached to the oesophagus, in the same 

 manner as we have indicated for several other species 

 of Phascolosoma. 



The observations of Dr. Teuscher on the Sipunculidæ 

 agree in most points with ours — only in a few points 

 they are rather different, namely with respect to the 

 cuticular bodies and the organs of generation. Dr. Teu- 

 scher supposes the cuticular bodies to be organs of sense. 

 To this we cannot agree; as we have shewn that they 

 are organs, which secrete mucus. The organs of genera- 

 tion are stated by him, in reference to the Sipunculus, 

 to be the longitudinal canals, which are found in the 

 skin, and which are formed by the layer of connecting 

 tissue of the skin in the central part of the wall of the 

 body, being only connate with the annular muscular 

 system at the places, where the longitudinal muscles run 

 under the annular muscles. In these longitudinal canals 

 he has found ova in various stages of development, and 

 is therefore of opinion that the ova are here developed. 

 As regards the Phascolosoma, he considers it probable 

 that the ova are produced from the epithelium, which 

 lines the perivisceral cavity. "We have previously given 

 our opinion explicitly concerning the longitudinal canals, 

 as well as concerning the organs of generation. 



*) Die Expedition zur physikalisch-chemischen und bio- 

 logischen Untersuchungen der Nordsee im Sommer 1872. Pag. 175, 

 Taf. 3, fig. 1—5. 



