ZOANTHARIA 



The longitudinal musculature is fairly well-developed but forms large folds. The parieto-basilar 

 muscles are moderately developed but in transverse section no folds are seen. The parieto-basilar and 

 longitudinal musculature extend a long way onto the body-wall. The micro-mesenteries are not very 

 well-developed. 



The filaments have the ustial structure. The glandular tract contains larger and smaller nema- 

 tocysts with greatly twisted thread, the larger are uniformly broad 31 43^ long and 12 14^, some- 

 times even 17 broad, and scarce to not seldom, the smaller are egg-shaped 1719^ long and 7 fi broad 

 and not seldom. Further, it contains thick-walled capsules with distinct basal part to the spiral thread 

 and broader at the one end than at the other (length 17 19/4 long, largest breadth 5^). Sometimes 

 also typical thick-walled capsules are present (length 24 ft). 



The sexual organs were not developed in the specimens examined by me. 



Besides the above-mentioned Isozoanthus-species a specimen of an Isozoanthus type which I 

 could not refer with certainty to any of the above-described was dredged at St. 2J during the Ingolf 

 Bxpedition. The polyp has a length of 2 cm. and a breadth in the capitular region of 0-4 cm., at the 

 base it measured crj cm. and was of a dark colour. The polyp was attached to a stone by an in- 

 considerable, irregularly triangle-shaped ccenenchyme on which a faint indication of another polyp was 

 visible. The large polyp gradually increased in breadth towards the capitular region which is some- 

 what rounded. The capitular furrows are indistinct. The oesophagus is short, the hyposulcus well- 

 developed. The body-wall at least in the upper part is greatly expanded and consequently thin. The 

 ectoderm is almost half as thick as the mesoglcea, continuous and incrusted with mud and detritus 

 particles, which partly at least give the animal its dark colour. The mesogloea is quite filled with 

 sand-grains and a few sponge-needles. It also contains numerous cell-islets and cells, but owing to 

 the strong incrustations it is very difficult to get a true idea of the nature of the mesoglcea. 



The sphincter resembles that of the other Isozoanthus-species. The oesophagus has the usual 

 structure. The ectoderm contains thick-walled capsules 19 22 n long. There are 36 mesenteries which 

 are very much expanded so that the mesogloea becomes very thin. The musculature seems to be 

 weak; the micro-mesenteries are well-developed. The filaments contain a few specific, uniformly broad 

 nematocysts (length 29 38, breadth 10 n /*) besides some more frequently occurring egg-shaped 

 capsules 13 15 n and thick-walled capsules with distinct basal part to the spiral thread and somewhat 

 broader at the one end (length ig//). The sexual organs were undeveloped. 



Owing to the small amount of material I have not named this form. 



Genus Parazoanthus Haddon and Shackleton. 



Macrocnemic Zoanthidae with a diffuse entodermal sphincter muscle. The body 

 wall is incrusted, the ectoderm is continuous. Encircling sinus as well as ectodermal 

 canals, lacunae and cell-islets in the mesogloea. Dioecious. Polyps connected by 

 thin coenenchyme, (coenenchyme without cylindric horny skeleton). 



