FROM THE GAULT. 



33 



The cpitlieca is waved and well developed. The spaces between the larger costce arc 



Locality. Gault, Folkestone. In the British Museum. 



Variety 2 (PI. XIII, figs. 3, 4). — The corallum is as large as that of variety 1, but it 

 is more conical. 



The costac are less pronounced, and the septa, which are more granular than those ot 

 variety 1, arise from the intercostal spaces. The costal ends are very elegant in shape, 

 and form a margin of rather sharp curves, side by side. 



Locality. Gault, Folkestone. In the British Museum. 



Variety 3 (PI. XII, figs. 1, 3, 4; and PI. XIII, fig. 13).— The corallum is rather fiat, 

 but hemispherical. 



The septa are not exsert, and they arise from the costal ends. 



The costae are equal ; none are more prominent than others. They are all rather 

 broad, flat, and beautifully ornamented with diverging curved lines. Their free ends arc 

 equal and curved. 



Locality. Gault, Folkestone. In the Collection of the Rev. T. Wiltshire, F.G.S. 



Variety 4. — The corallum and costas are like Variety 3, but the septa arise from the 

 intercostal spaces. 



Locality. Gault, Folkestone. In the Collection of the Rev. T. Wiltshire, F.G.S. 



Variety 5 (PI. XII, fig. 2). — The corallum is rather more conical iuferiorly than m 

 Varieties 3 and 4. 



The septa are exsert, and project slightly beyond the costal margin. 

 The costse are all rudimentary. 



The epitheca is well developed, and reaches up to the septa. 

 Locality. Gault, Folkestone. 



The forms may be distinguished as follows : 



more or less angular. 

 The peduncle is large. 



With nearly equal flat costse 

 Costac rudimentary 



With more or less ridged costae 



Variety 5. 

 The type. 



Septa arising from the costal ends 



Septa arising from the intercostal spaces 



