7. Anthozoa (incl. Hydrocorallia). A. Zoantharia. 21 



disc does not form a true creeping sole, and is not sharply marked off from 

 the column. The column- wall is covered with numerous, large, conical out- 

 growths; similar in appearance to these, but a little larger, are the tentacles, 

 of which 6+6 are endocoelic, and 12 are smaller and exocoelic. The conical 

 outgrowths are arranged in 24 longitudinal rows, corresponding to the endocrels 

 and exoco?ls. These outgrowths and the tentacles bear thin-walled nematocysts, 

 and agree in form and structure. The stomodseum and 2 siphonoglyphs are 

 well developed; each of the latter is continued as a gutter nearly as long as 

 the stomodaium. There are 6 pairs of complete and 6 pairs of incomplete 

 mesenteries. The aboral portions of them are so broad, that they are in 

 contact in the axial region and are incompletely fused, giving rise there to a 

 series of inter-communicating cavities. Filaments are present on the mesenteries 

 above (oral to) this region. Those of the 1. cycle are meandering, and com- 

 posed entirely of cnido-glandular tracts. The mesenteries of the 2. cycle bear 

 similar filaments along the greater part of their free edges, but in the oral 

 region there is on each mesentery a peculiar gutter-like outgrowth, covered on 

 its outer face by a continuation of the mesenteriat endoderm, and on its inner 

 face by long supporting cells and (especially in the groove) ciliated cells. The 

 mesogloea, which is here not sharply marked off from the cell-layers, contains 

 numerous nuclei. The parieto-basilar and mesenterial muscles are weak. 

 Ovaries, containing very numerous eggs, are present in the aboral region of 

 all the mesenteries. D. and the Protanthean genus Ptychodactis (from 



Norway) agree in the presence of the gutter -like structures on the 2. cycle 

 of mesenteries, in the absence of basilar muscle, in the corresponding positions 

 of their gonads, and in the similar structure of their mesogloea; they are referred 

 to a n. fam. Ptychodactidse. The presence in D. of a few mesenteries and 

 in P. of many is correlated with the form of the body, which in D. is elongate, 

 while in P. it is broad and short; the reduction of the stomodseum in P., and 

 its high development in D. are probably correlated with the proportion of breadth 

 and length of body in the 2 genera. The author discusses the principal, structural 

 features of Edwardsia, Protanthea, Boloceroides and Bolocera. The Ptycho- 

 dactidse, on account of their far-reaching progressive differentiation, must be 

 placed high in the Protanthese. The occurrence of the gutter-like outgrowth on 

 the 2. cycle of mesenteries in the Ptychod., shows that this family represents, 

 alateral offshoot of the Protantheae. 



Nafilyan records, with notes on their systematic characters, synonymy and 

 bionomics, from Roscoff: Edwardsia 1, Halcampa 2, Peachia 1, Mesacmcea 1, 

 Actinia 1, Ammonia 1, Bunodes 2, Tealia 1, Sagartia 2, Actinothoe 2 (2 n. var.), 

 Aiptasia 1, Gylista 2, Cereus 1, Calliactis 1, Adamsia 1, Gephyra 1, Corynactis 1. 

 Sag. elegans exhibits great variability; the author merges with this species, 

 miniata, venusta, rosea and nivea. He observed longitudinal fission in Acti- 

 nothoe pallida, and that, in specimens of Gephyra Dohrni, a portion of the 

 extended base developed a mouth and tentacles and became detached from the 

 parent. 



Pax( 1 ) gives a description of several of the Actinian types of Quoy & Gaimard, 

 and indicates their systematic position. Actinia clavus - Halcampa clavus, A. 

 cozrulea = Phymanthus car., A. parvitentaeulata = Radianthus p., and Mammil- 

 lifera viridi-fusca = Palythoa v.-f. and Zoanthus ccBspitosus (n.). 



Bamford describes a collection of Actiniarian larvae from the Indian Ocean. 

 There are 4 n. sp. of Zoanthina. In variabilis the mesenteries in the stomo- 

 daeal region are arranged on one side in the microtype, and on the other in 

 the macrotype manner, i. e., in the latter case, the mesentery next but one to 



Zool. Jahresbericht. 1912. Coelenterata. f 



