FAMILIES ATTD GENERA OE THE MADREPORARIA. 



189 



Distribution. — Fossil. Trias : Europe. Lias : England and 

 Europe. Oolitic : England and Europe. Cretaceous : England, 

 Europe, Asia. Eocene : Europe, Asia. Miocene : Tasmania. 



Subgenus OENTRASTRiEA, (genus) d^Orh. (1847). 



Thamnastrcea with an almost stjliform columella. 

 In recognizing this group care must be taken not to be 

 deceived by the results of fossilization, 



Grenus Clausastr^a, d'Orhigny, Note sur les Polyp, foss. p. 9 

 (1849), amended. 



Colony massive, with a plane or convex upper surface and 

 broad base. Corallites large, without definite walls, which are re- 

 placed by a cellular endotheca. Calices superficial, shallow, widely 

 open. Columella absent. Septa large, dentate, few, some con- 

 fluent with the septo-costse of the calices close by and others tra- 

 versing the intercorallifce space to reach somewhat distant calices, 

 straight, or geniculate, or curved here and there. Laminae short, 

 solid. Endotheca replacing walls here and there, and stretching 

 across the interseptal loculi high up like tabulae, but not passing 

 over the axial space. Synapticula small, short, stout, numerous. 

 Gremmation submarginal. 



Distribution. — Fossil. Jurassic : Europe, England. 



G-enus Psetjdastr^a, Beuss, Foss. Foram. Anthoz. von Oher- 

 burg^^ Denks. d. Kais. Ahad. der TViss. Wien, Bd. xxiii. 

 p. 24 (1864). 



Colony massive. Calices crowded, irregular, rather deep in the 

 centre, environed by a shallow groove, so that only occasional 

 septa become continuous with those of other calices. Septa den- 

 tate and numerous. Columella ends in a small irregular pimple 

 {Rocher). Pali in one crown. Synapticula exist, being placed 

 very regularly. (Endotheca does not exist, according to Eeuss.) 



Distribution. — Fossil. Eocene : Europe. 



G-enus Pironastr^a, d'AcJiiardi, Corall. Focen. del Friuli (Pisa, 



1875), p. 76. 



Colony lamello-discoid. Calices in concentric circles, confluent, 

 centres distinct and small. Columella absent, or as one papilla. 

 Septo-costse very large. Synapticula numerous. Endotheca 

 scarce. Epitheca well developed. 



Distribution. — Fossil. Eocene: Enrope, Sind, Asia. 



