FAMILIES AISTD GENEEA OF THE MADEEPORAEIA. 19 



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

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

 area during the Eocene. There are three species recorded from 

 the Lower Oligoceae 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 

 costse 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 

 SphenotrocJius resemble some of the Turhinolice with stout 

 costee, but the other distinctions are evident. 



There is a genus of M. de Fromentel'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 Turhinolia, This genus Stylotrochus (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 Sttlocyathfs, d'' Orhigny , Note sur les Polyp, foss. 

 p. 5 (1849). 



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

 Terr. Cret. pi. viii.). 



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

 The columella is styliform or compressed. 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. 



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



Pleurocyathus, Kefst., is not generically distinct from the 

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

 styloid columella. The only distinction is the presence of the 

 epitheca in Stylocyathus, d'Orb. E-euss named Pleurocyathus 

 Stylo cyathus, having been unaware of d'Orbigny's genus (see also 

 pages 26 and 27 of this Revision). 



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

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

 one of the Turbinolian alliance . 



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