358 Lindstrdm—On Zoantharia Rugosa. 



often broad, and form a faintly elevated ridge. This occurs 

 generally on the bottom surface, but is also seen on the others. 

 This ridge is partly formed by the border of the calyx folding 

 outwards at the point where the median strias occur. 



From the comers and also from the middle of the bottom 

 surface, there are seen to project narrow and bent processes, 

 resembling rootlets. They are very numerous towards the apex 

 of the shell, and thence decrease in number, disappearing near 

 the mouth of the calyx. These rootlets are hollow tubes, by 

 means of which the animal fixed its shell to other bodies.^ ' The 

 outline of the borders of the calyx, or the interior cavity (Plate 

 XIV. Figs. 1 and 2) has the figure of a regular trapezium with 

 rounded comers ; in younger specimens the corners are rectilinearly 

 cut off, which produces an octohedral figure. In attenuated speci- 

 mens the form of the mouth is nearly quadrate. The depth of the 

 interior cavity is very variable. In some specimens it occupies two- 

 tliirds of the total length, while in others of the same size, it is less 

 than half of that length. The four triangular lateral walls are 

 separated by shallow depressions, which, like the larger median 

 groove, are also called fosses sei^tales by M. Edwards. The upper- 

 most edge of these walls forms a border above the septse, within 

 which the operculum probably rested. A large septum^ projects 

 from the middle of each wall. Those of the largest and smallest 

 wall, opposite to each other, project the farthest, — they end at the 

 bottom of the calyx. The median septa of the lateral walls are 

 smaller ; on both sides of each of these four septa are seen a variable 

 number (9-13), of smaller septa, and, between these, others, still 

 smaller and fainter. These septa of the second order on the wall 

 are soon changed into narrow, punctuated, or irregularly indented 

 stria3, which in the bottom of the calyx intermingle and disappear. 

 On weathered specimens the septa appear as if cleft, or with a 

 groove in the middle ; this is occasioned by their being composed of 

 two lamella, which converge inwards in a sharp edge, and leave 

 between them an empty space, so forming the grooved appearance 

 when weathered. This is sometimes filled with calcareous spar. 

 At the bottom of the calyx, and also on the walls, sparse, faintly 

 elevated vesiculfe are seen, over which the narrow septa continue, 

 as in OmpJiyma MurcMsoni.^ The septal groove is situated close 



1 Such rootlike processes distinguish no less than eleven genera of the Cyatho- 

 pliyllina:, namely: — Cyathophyllion, Goniophyllum, Omphyma, Chonopliyllum^ Ptyeho- 

 phyllwn, Heliophyllum, Acervularia, Eridophyllum, Rhizophyllum, Axophytlum, and 

 several Cystiphylla. These rootlets either project from the convex side of the shell, 

 or are fixed all round it. Sometimes they have coalesced and are flattened into broad 

 curved hooks ("crampons," M. Edw.). Amongst the true Anthozoa the genera 

 Flabellum and Ehizoirochus alone have anything analogous. The description of the 

 rootlets of the Goniophyllum can be applied to all the above cited genera, but they 

 are perhaps not so remarkable in any one as in the new genus Ehizophyllum, about 

 to be described. 



^ The term "septum" is here used, without being considered homologous with the 

 parts so named in the Actinozoa. In the same manner " cardinal-raai'gin " is used 

 without indicating homology with the cardinal margin in the Mollusca. 



2 See Edwards and Haime, Brit. Foss. Corals, Plate 67, fig. 3 a. 



