PROM THE UPPER AND LOWER WHITE CHALK. 3 



MM. Milne-Edwards and Jules Haime, having all this information before them, very 

 properly admit the generic and specific names to be Caryopliyllia cylindracea, Reuss, sp. 

 C Hist. Nat. des Corall./ vol. ii, p. 18). 



This species is very polymorphic, and the pali of some specimens are very lUce the 

 outer terminations of the columellary structures in some JParasmilim. Very frequently it 

 is hardly possible to determine in Caryo;phyllia cylindracea which are pali and which the 

 ends of the columellary fasciculi. Moreover, in some specimens the base is small and the 

 costa3 reach low down, whilst in others the base is normal and large, the costse being 

 abnormal from their length. 



There is a new species of this genus in the Dunstable Chalk and another in the Chalk 

 of Sussex. There are thus three species of Caryophyllia in the Upper Chalk of England : 



1. Caryophyllia cylindracea, Reuss, sp. 



2. „ Lonsdalei, Duncan. 



3. „ Tennanti „ 



1. Caryophyllia cylindkacea, Beuss, sp. PI. I, figs. 7 — 12. 



Li the British Museum, Dixon Collection. 



2. Caryophyllia Lonsdalei, Duncan. PI. I, figs. 1 — 3. 



The corallum has a large and encrusting base, and the stem is cylindro-conical and 

 straight. There is a slight curve near the base. 



The calice is circular, small, not very open, and moderately deep. 



The columella is small, and is terminated by rod-shaped processes. 



The septa are slightly exsert, the primary especially. There are three complete 

 cycles, and the septa of the higher orders of the fourth cycle are not developed in every 

 system. The primary, secondary, and tertiary septa are very alike. They have a wavy 

 inner edge, and are granular. 



The pali are situated before the tertiary septa, and are knob-shaped and rather flat 

 from side to side. 



The costae are nearly equal at the calicular margin, and pass downwards as flat, band- 

 like prominences, separated by shallow intercostal grooves. They are continued to the 

 base, but are hidden midway by an epithecal growth. 



Height of the corallum, |ths inch. Breadth of the calice, 3rd inch. 



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



This species is readily distinguished by its costse, and is more closely allied to 

 C. cylindracea than to any other form. 



