FAMILIES AND GENERA OE THE MADEEPOBARIA. 129 



Astrseid nature of their type species, Plerastrcea Savignyi. Claus^ 

 astrcea has bow to be removed from the true Astrseidse, for it has 

 synapticula. Plerastrcea mirahilis, nobis, Foss. Corals &c. of Sind, 

 Pal. Indica, p. 65 (1880), cannot remain in its genus as deter- 

 mined by Milne-Edwards and Jules Haime. It is now Fratzia 

 mirabilis, and a Lophoseifine. 



G-enus Pleraste^a, Milne-Edwards Sf Jules Haime, Hist. Nat. 

 des Oorall. vol. ii. p. 553 (1857). 



Colony massive, turbinate, or flat, with a convex or subplane 

 upper surface. Corallites limited by Walls which are simple, 

 united, and well developed. Calices superficial. Columella 

 papillary. The septa few and subconfluent with those of the 

 neighbouring calices, dentated, uniting more or less. Dissepi- 

 ments well develoj)ed and abundant. An epitheca may exist 

 and be strong and folded. 



Distribution. — Fossil. Trias : Europe. Jurassic : England. 

 Eocene : Prance. — Subfossil. Eed Sea. — Recent. Eed Sea ? 



The next genus is a doubtful one. If it has no synapticula it 

 must remain ; but if it has, it is synonymous with Oentrastrcea, a 

 subgenus of Thamnastrcsa, Lesauvage. 



Genus HoLOCCEisriA, Milne-Edwards Sf Jtoles Haime, Brit. Foss. 

 Corals, Pal. Soc. p. 99 (1851). 



Colony massive, gibbous. Corallites united by their costae, 

 which are slightly developed^ or by their walls. The septa are 

 entire, have their upper edge nearly horizontal, and merge into 

 those of the neighbouring calices by means of the costae, with 

 which they are continuous. These septo-costse hide the summit 

 of the walls of the calices. The columella is styliform. 



Distribution. — Fossil. Cretaceous : Europe, S. India. Eocene : 

 Borneo. 



This is not a satisfactory genus ; see the admirable remarks of 

 its founders (op. czY. p. 99, 1851). The South-Indian Cretaceous 

 species has ragged septa and no synapticula. 



XIV. Alliance TABULOIDA. 

 Agglomerate Astrseidae increasing by gemmation. CoraUites united by 

 their walls. Dissepiments in the form of tabulae. Septa variable, in 

 cyclical arrangement. 



Genus Holocystis, Lonsdale. 

 Genus Coccophyllum, Reuss. 

 Genus absorbed : — Tetraccenia, d'Orb. 



LINK. JOUEN. — ZOOLOGY, YOL. XVIII. 9 



