ACTINIARIA joQ 



1,5 ft, those of the actinopharynx were numerous 18—24 X 1,5 fi resp. 22 — 29 X 1,5 (2) fi. The nematocysts 

 of the acrorhagi were of about equal length in both specimens 41 — 55 (i nematocyst 65) /i resp. 43 — 58 /i, 

 in breadth however different 2,5 jj. resp. 3 — 4 fx. There were moreover in the first specimen broader nemato- 

 cysts, to about 4 n, but they were more irregular and probably nematocysts in development. Also sparse 

 spirocysts are present in the ectoderm of the acrorhagi. 



The acrorhagi are perforated by an aperture as already shown by Dal yell. In sectionized arorhagum 

 of a specimen from the North Sea the aperture was aborally situated. At the aperture in the mesogloea there 

 was an annular wall, probably formed by the endoderm. The wall, wliich probably forms a movable stopping, 

 is turned outwards. Whether other apertures, cinchdes, are present in the upper part of the column I cannot 

 decide (compare Andres 1883, Simon 1892 and Pax 1908). A priori it may very well be so as the cinchdes 

 are not correlated with the acontia. Several Actiniaria namely have acontia but no cinclides, and others, as 

 Eloactis and Harenactis, have cinclides but no acontia. 



Fam. Boloceridae. 



Diagnosis: Basilaria with a well-developed basal disc. Column without sucking warts, acrorhagi 

 and pseudoacrorhagi. Sphincter from rather well-developed to strong, endodermal diffuse or circumscribed. 

 Tentacles at the base constricted and furnished with an endodermal sphincter, by the contraction of which 

 the tentacles are thrown off. 



This family is proposed by Mc. Murricli (1893) for the germs Bolocera. At the same time he suggested 

 that the Liponema of R. Hertwig was synonymous with this genus. Haddon (1898, p. 429) was of the same 

 opinion and this was further confirmed by myself (1899, p. 40), as I found some tentacles in the type-spec- 

 imen. Haddon moreover thinks that Polystomidium is very closely allied to Bolocera, and I myself gave 

 as my opinion 1899 that both genera are identical and that the presence of acrorhagi and the occurrence of 

 openings in the actinopharynx are the only characters through which Polystomidium is distinguished from 

 Bolocera. The presence of acrorhagi was doubted by Haddon (1898), and their absence was stated by mj^self 

 1899, when I had examined the type-specimen. To my mind the openings are of little importance, because 

 they probably are artificial products. As for me, I think that Bolocera and Polystomidium are synonymous. 



Later (1899) I proposed for Bolocera mc. murrichi Kwietn. a new genus Boloceroides which was re- 

 moved to the family Gonactiniidae, though I pointed out (1900) that the genus does not at all agree with the 

 typical Gonactiniidae. With the placing of Boloceroides among the Gonactiniidae Pax (1914, p. 608 and 

 Poche (1914, p. 97) agree, and Stephenson (1918a, p. 20) declares that it may be doubted, if the genus belongs 

 to the Boloceridae, though he thinks that its "position needs reconsideration." In a paper which I am 

 going to publish I will show that the family Ahciidae is heterogeneous — an opinion which I expressed 

 already 1898 and 1900 — I put Boloceroides together with Bunodeopsis, Alicia and Thaumactis in the family 

 Aliciidae, while Phymactis, Rivetia (= PPhymactis), Cystiactis, Phlyctenactis (= Cystiactis) and Eucladactis 

 (probably = Phymactis) are removed to a new family Cystiactiidae and Phyllodiscus to the Lebruniidae 

 (Dendromehdae) . 



A new Bolocerid genus, Boloceropsis, was estabUshed 1904 by Mc. Murrich. Concerning this genus 



1 8* 



