ACTINIARIA 



33 



the scapus between two mesente- 

 ries with a nemathybome (). 



Denmark. Samsobelt (Winther), Cattegat without distinct locality (Petersen). 



The Sound S. of Hven 9 fms. (Gunhild Exp. 1878 st. 33), S. of Hven 17 

 26 m; W.N.W. of Wiken ("Sven Nilsson" st. 30, 52 c). 



Exterior aspect. The physa is well-developed, the scapus provided with a thin periderm, with 

 which is combined a rather thick and soft layer, commonly ochre-coloured and probably, at least partly, 

 formed by closely -packed mucus-particles. The 

 comparatively few, but rather large nema- 

 thybomes are arranged in 8 longitudinal lines 

 as in E. tuberculata (textfigs. i6a, 19), quite 

 another distribution than in E. pallida (text- 

 fig. 16 b) . The nemathybomes are generally 

 distinct, only if the animals are very con- 

 tracted or the periderm is loosened from the 

 ectoderm, it is sometimes difficult to discern them. Also in contracted specimens the nemathybomes keep in 

 the main the same position, though they are often a little displaced and approached to each other. The upper 

 part of the column at stronger contraction shows a polygonal appearance which is more distinct in extended 

 specimens. 



The tentacles are almost always 16, arranged in 2 cycles as in E. claparedii (compare textfig. 10) ; 

 in a very small (0.4 x 0.15 cm), but fertile specimen from Samso belt, sectioned by myself, I have not found 

 more than 12 tentacles. Thus it looks as if the species could be ripe already in a stadium with 12 tentacles 

 and with more than normally weak mesenterial muscles (compare below) 1 , at least in the Danish seas, 

 where the genus moreover does not reach the same size as in Bohuslan. Perhaps we here meet with the same 

 case as in Halcampa duodecimcirrata which is ripe in a stadium with only 8 perfect mesenteries and 10 tentacles 

 (Carlgren 1893 a), at least at our coast, where it is smaller than at the coast of Norway. The tentacles are 

 conical and, in comparison with those of E. pallida, long (the name longicornis, however, does not indicate 

 that the tentacles are longer than in the Edwardsia-species in common), the inner endocoel-tentacles are about 

 two thirds as long as the outer exocoel-tentacles. The oral disc is conical and provided with radial furrows 

 corresponding to the insertions of the mesenteries. The actinopharynx as usual is furnished with 8 longitudinal 

 furrows, the ventral one of which forming a weak siphonoglyphe. 



Anatomical description. The nematocysts of the nemathybomes are of two kinds, one shorter 

 and thinner and of almost equal breadth, the other longer and broader and of different breadth at the basal 

 and at the distal end, the latter the narrower. The size of the nematocysts and the spirocysts in the different 

 parts of the body appears from the following table (see page 34). 



The 8 " Edwardsia-mesenteries" are provided with well-developed, in transverse sections not elong- 

 ated, longitudinal pennons. The highest folds appear as usual at the outside of the pennons, in the innermost 

 part there is often also one high fold. The number of the folds in the upper part of the reproductive region 



1 It may be possible that we have to do with a distinct species here, but my material is too poor for deciding it. The 

 parietal muscles of the Samso specimen recall those of E. danica. 



The Ingolf Expedition. V. 9. c 



