FAMILIES Al^J) GENERA OP THE MADEEPORAEIA. 19 



There is a very marked facies in all the species of Tiirhinolia, 

 which are eighteen in number, eleven having lived on the English 

 area during the Eocene. There are three species recorded from 

 the Lower Oligocene of Grermany. 



The number of septa is not great, and the species may be 

 grouped under four heads : — Those with four cycles incomplete ; 

 those with three cycles ; those with three cycles of septa and the 

 costsB of a fourth cycle ; and those with the third cycle of septa 

 incomplete. The columella is a styloid process arising from the 

 base within, and some septa always unite with it. 



The genus is comparatively isolated ; some species of the genus 

 Sphenotroclius resemble some of the Turhinolicd with stout 

 costse, but the other distinctions are evident. 



There is a genus of M. de Eromenfcel's, which was established 

 from a single specimen of one species. It only differs from Tur- 

 hinolia in having a curved cornute corallum and no ''fossettes " 

 between the costse. This last character is not invariable in the 

 genus TurhinoUa. This genus StylotrocJius (Pal. Erang., Zooph. 

 Cret. pi. viii.) is of Cretaceous age, and I place it as a subgenus. 



Sismondi names a species from the Italian Tertiaries. 



Grenus Sttlocyatieijs, d'' Orhigny ^ Note mr les Polyp, foss. 

 p. 5 (1849). 



Syn. PleurocyatTius, Kefst. (de Eromentel, Pal. Erang., Zooph. 

 Terr. Cret. pi. viii.). 



The corallum is subturbinate, subpedicellate, curved, and free. 

 The columella is styliform or comj)ressed. The septa are exsert, 

 and there are pali before all the cycles except the last. An 

 epitheca is well developed, and extends more or less to the cali- 

 cular margin. 



Distribution. — Fossil. Cretaceous, Eocene, Oligocene : Europe. 



JBleurocyatJius, Kefst., is not generically distinct from the 

 above. It is straight, free, has costse which are smooth, and a 

 styloid columella. The only distinction is the presence of the 

 epitheca in StylocyatJius, d'Orb. E,euss named Pleurocyathus 

 Stylo cyatJius^ having been unaware of d'Orbigny's genus (see also 

 pages 26 and 27 of this Eevision). 



There is a great difiiculty in placing the next genus with any 

 of the alliances of the Turbinolidse ; and it had better come in as 

 one of the Turbine lian alliance . 



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