144 



The specimen at hand measures, though the posterior end is 

 wanting, 7 cm in length by 1,5 cm in diameter. The length of 

 the lacking end may not be rather large, as the posterior end of 

 the loop of the intestine is present. Thus the specimen has probably 

 not been more than ca. 10 cm long. The colour is in alcohol 

 brownish grey, and there is no distinct difference in the colour of 

 the dorsal and ventral side. The tentacles are somewhat darker 

 than the body. There are 24 tentacles, each with 16 — 18 pairs 

 of digits. As the tentacles are much contracted, it is not possible 

 to see whether the digits are united by a web or not. On the oral 

 disk there are weak eye-spots at the base of the tentacles. The 

 cartilaginous ring is large and has foramina close to the posterior 

 margin. The calcareous ring is unusually stout and consists of 24 

 pieces, one for each tentacle. The radial pieces are very like the 

 interradial ones, apart from the perforation for the nerves, but are 

 wider than the interradial pieces in their anterior end. Furthermore 

 the outline of the anterior margin of the radial pieces is slightly 

 different from that of the interradial ones (Fig. 12. 3). Selenka's 

 statement that the calcareous ring consists of "25 einander gleichen 

 Stücken" (cf. Selenka's figure Taf. XX fig. 120), therefore is not 

 correct. Further Selenka draws, in the left side of this figure, 

 the tentacles in the prolongation of the pieces of the calcareous 

 ring, whereas in reality the tentacles are placed off the intervals 

 between the pieces of the calcareous ring; their muscles being 

 thus attached with one half to each two adjoining pieces of the 

 ring. On the exterior side of the calcareous ring there are no 

 muscular impressions, but the area to which the tentacle-muscles 

 are fastened is usually a little darker than the rest of the ring. 

 There are many polian vesicles and a single stone-canal. The 

 madreporite is short and thick and therefore different from the 

 madreporites in the other species represented, which are rela- 

 tively longer and also prolongated along the stone-canal. Whether 

 this has any systematical value in this genus, or not, it is not 

 possible to state from the material at hand. The gonads are long 

 and thin and branched several times. The alimentary canal may 

 be divided into three distinctly different parts. The oesophagus is 

 rather long and narrow with thin walls. The stomach is wide and 

 with thick and glandular walls, and the long intestine is very thin- 



