6o 



ZOANTHARIA 



CESophagus were 24—26// long. The filaments contained very few capsules 41 fi long and 18 a broad 

 like those in the bodj-wall and fairly many 19— 22 « long and thick- walled. In a polyp closely examined 

 by me the number of mesenteries was 42 (20 on the one side and 22 on the other). 



In the collections of the Riksmuseum there is a small colony of a Parazoanthus species from 

 the Faeroes, but badly preserved. The nematocysts mostly resemble those of P. haddoni , but might 

 quite well belong to P. anguicouins though not to P. dixoni, as they agree with the shortest ones in 

 P. haddoni and anguiconms, while those of dixoni agree better with the longest ones. A transverse 

 section of the body-wall of this form is given in fig. 6, PI. VII, of this paper. 



Appendix. 



During the printing of this work a paper has appeared dealing with the genus Epizoanthus 

 (L, wow sky: Revision der Gattung Sidisia Gray (Epizoanthus Auct), Zool. Jahrb. Abt. Sy.stematik 

 Bd. 34, pp. 557 — 614, 1913). As this paper among other things sets up a new diagnosis for the genus 

 I wish to discuss here the extent of this genus. 



With regard first of all to the name, the author has replaced Epizoanthus with Sidisia, a change 

 that would be justifiable according to modern rules of priority, if the type of Sidisia, S. barlrsi] were 

 in realit)- identical with E.iiicrustatus. Haddou and Shackleton (1891) certainly state, that this is 

 the case, but they nowhere indicate, that they have had type specimens of .S*. /^ci'r/rj/ for investigation. 

 For this reason, as also that the Zoanthidae are difficult to determine from outer characteristics, I have 

 above used the name Epizoanthus instead of Sidisia. Moreover I am in agreement with Haddon (1891, 

 p. 634): "We do not propose to keep the name Sidisia for the genus, although it has priority and for 

 this reason; it was solely erected for a species which is only a variety of an older form; and the name 

 has only been occasionally retained for this variety of that particular species, whilst Epizoanthus has been 

 universally adopted for the more typical forms of this genus. Both names were originated by Gray 

 and we have therefore less hesitation in keeping to the latter". 



In his diagnosis of the genus vSidisia Lwowsky states, that the sphincter in its proximal part 

 may be entodermal as also that an encircling sinus may occasionally be jiresent; he relies here on his 

 investigation oi S. (gracilis. But in my o^xmow S. gracilis is in all probability not a SidLsia but a Para- 

 zoanthus species. So far as I can find, namely, the sphincter figured of E. gracilis is not a mesogloeal 

 but an entodermal structure. That it seems mesoglceal in the distal part is due to this, that the 

 section has cut through not only the body-wall but also a mesentery. And since the entodermal 

 sphincter in the genus Parazoanthus becomes mesogloeal from cutting through the raesogloea of the 

 mesenteries, a great part of the sphincter in sections which just meet the mesenteries may have the 

 appearance of being a weak mesogloeal .sphincter. Such figures, like that drawn by ly wow sky for 



