38 



ZOANTHARIA 



Epizoanthus koreni n. sp. 



PI. 2 fig. 2 3 , PI. 4 fig. 4. 



Occurrence: 62°49' N., 7°i2' W. 276 fms. Bott. temp. r6°. Ingolf Ex. St. 144 1 colony of 

 two polyps. 



Dimensions: Length of the largest polyp ri cm; smallest breadth 0-35 cm.; largest breadth 

 0-55 cm. 



Colour in alcohol: dirty sand-coloured. 



External appearance. The ccenenchyme was large and covered among other things an 

 arm of an Ophiurid. It is fairly thin but has a very robust appearance, probably owing to the imbedded 

 small foreign particles on which it grows. The 2 polyps are not close to each other but separated by 

 a fairly great interval. The largest polyp is elongated, almost double as long as broad, narrow at the 

 base but gradually increasing in breadth upwards. The smaller polyp on the other hand is higher 

 than broad and more cylindrical. The capitular furrows are distinct, in the largest specimen their 

 number was 18, in the smaller probably 15. The upper margin of the polyps is truncate, the tentacles 

 being retracted. The incrustation is inconsiderable and restricted to the outer part of the body-wall. 



The oesophagus is short, siphonoglyphe and hyposulcus distinct. 



Anatomical description. The ectoderm of the body-wall is fairly high, continuous and 

 incrusted with sand-grains, sponge-needles and foraminifera , though not very strongly. It is also 

 incrusted with detritus particles attached to the cuticle. The ectoderm frequently contains nematocysts 

 with coiled thread, in the capitular region these are scarce. They are uniformly broad 26 — 29 it long, 

 about 10 /x broad and rounded at both ends. The mesoglcea is thick and considerably thicker than 

 the ectoderm; only the outer part of the mesoglcca has a slight incrustation consisting of the above- 

 mentioned particles. The mesoglcca contains numerous oval or round cells and fairly many, middle- 

 sized cell-islets, and rarely large cavities filled with round or oval cells, the nature of which I have 

 not been able to determine with certainty (PI. 4, fig. 4 ml?). The entoderm is fairly large and seems to 

 contain zooxanthellse , which however are more numerous in the entoderm of the oesophagus and the 

 mesenteries. In the mesoglcea of the mesenteries similar cavities filled with cells may also occur as 

 in the mesogloca of the body-wall. 



The sphincter is very strong and resembles the sphincter in E. erdmanni. It lies considerably 

 nearer to the ectoderm than the entoderm. 



The ectoderm of the tentacles contains great numbers of spirocysts but only few thick-walled 

 capsules (length about 19/^) and nematocysts with much coiled thread (length 26—31^, breadth io/<). 



The oesophagus has the usual structure. I have not been able to make any macerated prepara- 

 tions of the high ectoderm. The siphonoglyphe is deep with thinner ectoderm and considerable thicker 

 mesoglcea than in the oesophagus. 



In the specimens examined anatomically the number of mesenteries (in the large polyp) was 

 36, 10 macro and 8 micro on either side of the directive line. The micro-mesenteries are moderately 

 developed, the macro-mesenteries strong. The longitudinal musculature on the macro-mesenteries is 

 fairly strong, but not much folded, the parieto-basilar musculature is weak. The distribution of the 

 longitudinal and parieto-basilar musculature on the body-wall is inconsiderable. 



