58 



11. Eiiiigiacyatlius fragilis. M. Sars. 



nov. gen. et sp. 

 (PI. V. fig. 24-32). 



Of the free Turbinolidse, of which most species are fossile, and which in the present 

 telluric period belong almost exclusively to the wanner seas, we have formerly known only 

 one single northern form, namely the Uloryathus ardicus described by my Father^ and con- 

 sidered after later investigations, to be identical with the fossile coral classed by Milne Ed- 

 wards & Haine^ under the denomination Flabellum laciniatum, which has been found by Phi- 

 lippi in the tertiary formation of Calabria. It is therefore interesting to state the existence 

 of another remarkable coral Itelonging to the same group, and living together with the former 

 in the great defiths olf our coast. It forms the type for a proper genus, which was named 

 by my Father Fungiacyathus on account of a very striking external similarity to the well 

 known tropical genus Fungia belonging to another family. 



My largest specimen has a transverse diameter of 21 Mm. 



The polyparium or the calcareous skeleton (fig. 29. 30) has completely the appear- 

 ance of a Fungia, its base forming (fig. 25. 27) a horizontal flat, nearly circular disc, to the 

 upper side of which the radiating lamella' (septa) are attached, without being enclosed by 

 the so-called wall leaf (characteristic for most other stone corals) which forms the outer 

 boundary of the calyx (theca) and gives it its form. In our coral there can therefore be no 

 question of any calyx properly speaking ; because the calyx is precisely dependent on a more 

 or less perpendicular wall-leaf which is here entirely wanting, or strictly speaking exists in- 

 deed, but by being extended in the same horizontal plane, loses its character, and only re- 

 presents the liase of the coral or a so-called foot-leaf. The coral is therefore below quite 

 flat, while above it is rather strongly convex (see fig. 29) which however is only owing to 

 the high salient septa proceeding from the foot-leaf, which from the border rise rather ab- 

 ruptly, and then again become more gradually lower towards the centre, thus forming a wide 

 and deep central cavity (fossa calicinalis) in the middle of the upper surface. These septa 

 are very numerous, particularly thin and brittle, with the free border in its whole length some- 

 what wavy, and rather regularly folded or corrugated transversely; so that the free edge 

 seen from above (fig. 31) appears zigzagged. They all remain in their whole length separate 

 from each other, without any anastomosis ; and have usually a tolerably straight direction 

 converging from the border to" the centre like radii of a circle'. Only exceptionally some of 

 them are somewhat irregularly sinuous in a part, or in the whole length of their course, and 

 this stands usually in connexion with an irregularity in the exterior border of the coral. As 

 usual () systems can be distinguished, and in each of these — s orders of septa. The 6 

 primary septa (fig. 24. 29. 30. 1) are in most cases easily defined ; although it often happens 



' F.iun.a littoralis Norvegise Vol. 2. p.ig. 73. Tab. 10. Fig. 18 — 27. 

 '^ Annalcs ilcs sciences natiDTlles, 3*^ scrir, T. 9, pag. 273. 



