ACTINIARIA 

 132 



stages to at least certain species described as Phellia, very likely not a homogeneal genus. Besides it does 

 not seem improbable that the Sagartids including at present all Actiniaria with basilar muscles and sphincter 

 are of polyphyletic origin, a suggestion which, however, requires closer examination in order to be confirmed 1. 

 To tliis family I think that also the genus Octineon Mosel, belongs. In fact this Actinia is not as re- 

 markable as Fowler supposes and as I can confirm from my own examination of type-specimens. The basal 

 disc and the column, both incrusted with grains of sand, have no doubt an ectoderm, though the strong 

 incrustation makes it difficult to ascertain its true nature. It is besides difficult to get a good figure of the 

 ectoderm because the cuticle of the scapus, viz. the incrusted part of the column, is very strongly folded. 

 On the sections it seems as if the scapus is provided with "i/afc«m/)fl-papillae". On the other hand, Fowler 

 supposes that a secretion of mesogloea by wandering cells from the endoderm takes place for the adhesion 

 of the sand — he declares, however, that he has not observed any such cells. The capitulum is short, without 

 a cuticle and probably without spirocysts. The sphincter is very elongated, mesogloeal, with, especially in 

 certain places, scattered meshes. The tentacles are 12, of which 6 are primary-endocoel and 6 exocoel tentacles. 

 They are capable of invaginating like the tentacles of Halcampoides. Their ectodermal muscles are ^•ery 

 weak. Like Fowler I have not observed any distinct siphonoglyphes. The number of mesenteries is in the 

 proximal part very great, this is closely correlated with the large diameter of the basal disc. In one specimen 

 I counted 157 mesenteries in this part, thus a much greater number than stated by Fowler. Two cycles 

 of mesenteries in the examined specimen reach the capitular region. Of the mesenteries of the first cycle 

 only the 8 "Edwardsia-m&s&nt&ri&s" are perfect, as far as I can see. Fowler declares that some of the weaker 

 mesenteries are attached to the actinopharynx, and also the four couples which, together with the 8 "ft^- 

 t£iflri?sia-mesenteries", form the 6 pairs of mesenteries of the first order. Still on Fowler's reproduction 

 (fig. 12, PI. 30, 1888), only the six first pairs are connected with the actinopharynx. According to Fowler 

 the section liits the actinophar>'nx. It is, however, questionable whether it really is so, I am more inclined 

 to think that the section is more distal — a mistake which may easily have occurred to Fowler as he de- 

 clares that "in the histological conditions no differences are apparent between the stomadaeum and the oral 

 disc", and the strong contraction of this part has rendered it more difficult to examine the insertions of the 

 mesenteries. In fact the actinopharynx is easily distinguished from the oral disc, because the former is devoid 

 of ectodermal muscles, while the latter has such. In the best preserved specimen, sectioned by myself, only 

 the 8 " Edwardsia-xa&SQnt&nQs" certainly were perfect, and besides, no mesenteries but these reach the inner 

 part of the oral disc. As to two other sectionized specimens I cannot determine the number of the perfect 

 mesenteries, on account of the bad preservation and the animals being torn asunder in the region of tlie 

 actinopharynx. Nevertheless it is not impossible that, in certain cases, some more mesenteries may be 

 attached to the actinopharynx, it is namely to be observed that no reproductive organs were developed in the 

 above-named specimen. As, however, this was one of the largest specimens and furnished with very nume- 

 rous mesenteries I think that there is little reason to suppose that possibility. The 8 Edwardsia-m.^e.ntenes 

 have very strong, in transverse-section perfectly circumscript, muscle-pennons, filaments and reproductive 

 organs, the ventral mesenteries of the dorso-lateral pairs (the 5th couple), according to Fowler, has only 



' compare p. 19. 



