lxxiv BRITISH FOSSIL CORALS. 



2. Genus Mortieria. 

 De Koninck, Anim. foss. du Terr, carbon, de Belgique, p. 12, 1842. 



Corallimi having the form of a bi-concave disc, presenting a radiate structure and 

 numerous costae. 



Typ. sp., Mortieria vertebralis, De Koninck, loc. cit., pi. b, fig. 3. 



3. Genus Cyclocrinites. 



Eichwald, Uberdas Silurische Schiehten-System in Estkland, p. 192, 1840. 



Corallum composite, astreiform. Calices hexagonal and shallow. Septa well charac- 

 terised, but not extending to the centre of the visceral chamber, which appears to be 

 occupied by small tabulae. (?) 



Typ. sp., Cyclocrinites Spaskii, Eichwald, Die Urwelt Russlands durch abbilduugen erlaeutert, p. 48, 

 tab. i, fig. 8, 1842. 



Order 11. 

 ALCYONARIA. 



Alcyoniens, Audoain and Milne Edwards, Recherches sur les Anim. sans Vertebres faites aux ilesCbausay, 

 Ann. des Sc. Nat., 1st series,, vol. xv, p. 18, 1828; Zoophytaria, Blainville, Mauuel d'Actiuologie, p. 496, 

 1834 ; Zoo-phyta astero'idea, Johnston, Brit. Zooph., p. 164, 1838 ; Alcyonaria Dana, Exploring Expedition, 

 Zooph., p. 586, 1846 ; Anthozoa astero'idea, Johnston, Brit, Zooph., 2d edit., p. 138, 1847. 



Polypi with bi-pinnate tentacula, and only eight perigastric membranaceous laminae, 

 containing the reproductive organs. 



Alcyonaria have, in general, their dermal tissue consolidated by isolated spiculae or 

 nodular concretions only, and very rarely present a vaginal polypidom similar to that of 

 the Zoantharia ; but even when that is the case, the visceral chamber is never subdivided 

 by any longitudinal septa, and consequently the caiice never presents any appearance of 

 radii. In general, the corallum is entirely composed of epidermic tissue, (or basal secretion, 

 Dana,) and constitutes a sort of stem or axis in the centre of the compound mass formed 

 by the gemmation of the Polypi. This sclerobasis is always covered by soft dermic 

 tissue, and increases by the addition of concentric layers. 



This order is far from being as numerous as the preceding division of Corallaria, and 

 comprises three natural families, — Alcyonidae, Gorgonidae, and Pennatulidae. 



