22 ZOANTHARIA 



the oesophagus and its differentiations. The ectoderm and the mesogloea are incrusted with sand-grains, 

 foraminifera and a fairly large number of sponge-needles. In e and f sand-grains were almost 

 exclusively present. The incrustation is often considerable and fills almost the whole of the mesogloea. 



The sphincter is very strong and has some resemblance to the sphincter in E. erdmanni. 



The tentacles have the usual structure. The spirocysts of the ectoderm are very numerous. 

 Besides there generally occur some thick-walled, equally broad nematocysts (length 17 — 19^^) and more 

 seldom nematocysts of the same type as in the capitular region of the body-wall (length 38—48 ^, 

 breadth 7 [i). The ectoderm of the oesophagus is high and contains large numbers of equally broad 

 nematocysts with greatly twisted thread (length (38) 43—48 [i breadth 7 //). Further, very numerous 

 typical thick-walled nematocysts occur (length 24 (26) ;«). The mesogloea is thick. The ectoderm of 

 the siphonoglyphe is of the typical appearance, the mesogloea thick, though very little thicker than 

 that of the oesophagus. 



The number of mesenteries was 38 in the specimen sectioned, on one side 11 macro and 9 

 micro-mesenteries, on the other 10 macro and 8 micro-mesenteries. In the larger specimen of the 

 colony the number was presumably 36 (it was opened partially lengthwise). Another from colony c 

 had 36, specimen d about 40. The micro-mesenteries are well-developed in the oesophageal region. 

 The mesogloea of the macro-mesenteries is fairly thick, the entoderm thin. The longitudinal muscul- 

 ature is moderately developed and forms few folds; in one specimen from colony c which had a very 

 wide oesophagus and the mesenteries consequently very contracted in breadth, the musculature lay in 

 thick folds, the mesogloea being also here thicker than in a, where the mesenteries were much ex- 

 panded in breadth. The parieto-basilar muscles are very weak. The distribution of the mesenteric 

 muscles on the body-wall is fairly considerable. 



The filaments have the usual structure. The glandular tract contains numerous, equally broad 

 nematocysts with greatly twisted thread (length (34) 38 — 49 (53) //, breadth 6 — j fi). I have not observed 

 any thick nematocysts resembling those found in the lower part of the body-wall, if on the whole 

 they occur they must be very scarce; in one specimen I have found a single one (length 36 /i, breadth 

 II n). Further, many thick-walled capsules occur here with distinct basal part to the spiral thread, 

 broadest in the one end (length about 22 (19 — 24) ,«, sometimes 26//, breadth about ^ — 6[i). The 

 polyps arc dioecious, one of the specimens examined was a male with developed testes. 



Systematic remarks. This .species is closely related to E. danielsseni, from which it differs 

 however in external appearance, especially in the form of the coenenchyme and with regard to the 

 structure and distribution of the nematocysts and the mesenteries. As in E. danielsseni the capsules 

 in the lower part of the body-wall and in the capitular region are different in this species. 



var. iiordgaardi PI. 2, fig. 7. 



As already pointed out above, the external appearance of E. lindahli is very much like that 

 of E. erdmanni. At Lyngen Dr. Nordgaard has collected material of a Zoantharia which I determined 

 as E. erdmanni (Carlgren in Nordgaard. Hydro, and Biol. Invest. 1895, p. 159). Two of the specimens 

 in the collection I retained for the Riksmuseum in Stockholm. On closer examination, however, it 

 appeared that the one specimen was not E. erdmanni but a species which must be closely related to 



