]() TjrÉEL, NORTHERN AND ARCTIO TNVERTEBRATES. TI. PRIOPULJDS, ECHIUR1DS ETC. 



The following excerpts from the text of Danielssen and Koren may serve as 

 a supplement to the characteristics just referred to. With regard to the proboscis 

 and the clefts they write: ». . . . appendix (the proboscis), constituting a hollow, semi- 

 translucent tube, 30 mm. long and about 1 mm. thick at the base ; elsewhere 0,8 mm. 

 throughout its length to the extreme point, which is a trifle slenderer, and in .which 

 the tube terminates ceecally». . . »Immediately posterior to the basal portion of the 

 proboscis, on either side of the trunk, is seen a cleft or fissure, about 2,6 mm. in 

 length. and somewhat arcuate, the anterior extremity, which is narrower than the 

 posterior, slightly inclining towards the dorsal surface ; it has comparatively thick 

 edges, near together but not contiguous. » 



»The bottom of this fissured opening was apparently pierced with diverse mi- 

 nute apertures, which, however, had become so shrunk and contracted (the specimen 

 was preserved in spirits) that even under a powerful lens they could not be plainly 

 distinguished.» Consequently the authors were not able to state the presence of 

 such holes or apertures. Nevertheless, they ascertain in the > Generic Character» that 

 the bottom of the fissures is pierced with »several apertures» and their figures 11 

 and 12 (Pl. VI) exhibit, that there should be four very distinct holes in the bottom 

 of each cleft. A singular contradiction ! 



Furthermore, the Norwegian investigators inform us of the facts, that the body- 

 wall is almost devoid of a chitinous cuticle — according to them, it is »hyaline, 

 without strise, and on the trunk exceedingly thin, so thin indeed as to be with dif- 

 ficulty distinguished even under a strong magnifier* — , that the intestine »is exce- 

 edingly wide, occupying a considerable portion of the perivisceral cavity», that »it 

 protends almost straight back towards the posterior extremity of the body, where 

 it opens into an exceedingly short rectum, with a round anal aperture »and that» it 

 is furnished throughout its entire length on the ventral surface, and on the sides, to 

 within a millimetre or two from the anal opening, with numerous broad annulary 

 folds, figs. 10 a; 11, d, projecting far down into the lumen of the intestine». Fur- 

 thermore they say that the dorsal surface of the intestine, on the other hand, is 

 smooth, and furnished on the outer surface with an exceedingly muscular band, 

 closely webbed by numbers of membranous and muscular filaments to the dorsal 

 surface of the perivisceral cavity, no space being left between the latter and the 

 intestine » . 



The referred statements of Danielssen and Koren may be sufficient for un- 

 derstanding that the Epithetosoma is not related to the Gephyreans. 



On the other hand, the sum of the statement of Danielssen and Koren in- 

 dicates that the animal in question may be a Nemertean, its »tubiform appendix» 

 represen ting the protruded proboscis of the Nemerteans, the two »clefts or fissures» 

 being the two ciliated fossje characteristic for these animals, the »uterus» being the 

 proboscis sheath etc. The straight intestine too with its lateral dilatations seems to 

 confirm this assumption. Consequently I entertain the opinion that the family Epi- 

 thetosomatidcB must be excluded from the Gephyreans as being non-related to them. 



