CERIANTHARIA. 



Occurrence: Norway Trondhjem fjord Rissen 130111. slime, 21.7.1892 G. Svenander. i sp. (A). T. M. 



i sp. T. M. 



Kattegat (No. 432) Joh. Petersen i sp. (B) labelled C. borealis Dan. Cop. M. 

 (No. 432) i sp. (C) C. incmbranaccus Cop. M. 



(No. 424) i sp. (D) C. borealis Dan. Cop. M. 



(No. 318) i sp. (E) Cop. M. 



Dimensions. Sp. A. Length of body 15-5 cm., greatest breadth 3 cm. Length of marginal ten- 

 tacles: the innermost 6-5 cm., the outermost 3-5 cm. Length of labial tentacles 1-4 17 cm. Length of 

 stomatodaeum about 3 cm. - - all measurements taken from preserved specimens. 



Colour: According to the statement of Dr. Svenander, who dredged a specimen in Trond- 

 hjem fjord, the whole animal was of a faint flesh colour. 



Exterior aspect (PI. i, fig. i). The body has the usual aspect of the Cerianthidae. The column 

 shews longitudinal furrows as a result of contraction. Such may possibly be observed in the fully 

 extended animal, as in the well extended upper portion feeble longitudinal furrows appear, which are 

 specially well marked below the tentacles and there correspond to the insertions of the mesenteries. 

 Aboral pore? The tentacles are long, the marginal and labial tentacles each 160170. The marginal 

 tentacles seem to be arranged in the same way as with C. membranaceus. As regards the grouping 

 of the labial tentacles however, I cannot express myself with any certainty, as I did not like even in 

 the slightest degree to mutilate the only well preserved specimen (A). As this specimen happened 

 to be dissected along the line of the siphonoglyph some tentacle insertions were also damaged, which 

 was a great difficulty in the investigation of the arrangement of the labial tentacles. In an- 

 other specimen, which was fairly well preserved but strongly contracted, it seemed to me that some 

 tentacles in the region of the directive mesenteries were wanting. Though it is possible that the 

 directive chamber and the two contiguous chambers lack labial tentacles, I prefer to leave the arrange- 

 ment of the labial tentacles in this species an open question. 



The stomatodaeum is of medium length with feeble longitudinal furrows in the oral portion, in 

 the aboral with deep furrows and between them high ridges running lengthwise. The aboral end 

 of the stomatodaeum is bent towards the column in the sort of way often noticed in contracted Ceri- 

 anthidae. The siphonoglyh is comparatively narrow, so that only 6 mesenteries are attached to it 

 The hyposulcus is very short, though the hemisulci are comparatively long, but so narrow that they 

 look like filaments for the greater part of their course. 

 Anatomical structure. 



Column: The ectoderm is thick with numerous nematocysts, with marked spiral thread. The 

 length and breadth of the nematocysts vary considerably. The largest size had a length of 96^ and 

 a breadth of 27//, the smallest size was 58^ long. The ectodermal musculature is very fully developed, 

 in the highest part of the body the folds are twice as high as the rest of the ectoderm, but, as usual 

 with the Cerianthidae, taper off considerably in the distal and proximal part of the animal. The 

 mesogloea-lamellae supporting the muscles are very fine and are set extremely close together. The 

 chief lamella of the mesogloea is thin. The endoderm is rather thinner than the epithelial portions 

 of the ectoderm and in the region of the stomatodaeum furnished in sections with tongue-like pro- 



