INTRODUCTION. lxvii 



7. Genus Hallia. 



Corallum tall, turbinate. Septa highly developed, and extending to the centre of the 

 tabulae. No columella. One remarkably large primary septum occupying the place of the 

 septal fossula, and the neighbouring septa directed towards it, so as to assume a pinnate 

 arrangement ; the septa belonging to the two other systems presenting the usual regular 

 radiate position. 



Typ. sp., Hallia insignis, nob. 



8. Genus Aulacophyllum. 



Corallum resembling Hallia by the mode of arrangement of the septa, but having the 

 septal fossula not replaced by a primary septum, and affecting the form of a narrow groove, 

 at the bottom of which the septa of the two adjoining systems meet, and even cross each 

 other. 



Typ. sp., Aulacophyllum sulcatum ; Caninia sulcata, D'Orbigny, Prod, de Paleont., vol. i, p. 105. 



9. Genus Trochophyllum. 



Corallum simple, trochoid. Calice rather shallow. Septal fossula rudimentary, and 

 occupied by a small septum. The other septa thick, not denticulate, presenting a regular 

 radiate mode of arrangement, and extending almost to the centre of the visceral chamber, 

 where a small tabula is visible. 



Typ. sp., Trochophyllum Verneuili, nob. 



10. Genus Hadrophyllum. 



Corallum short. Calice superficial. One very large septal fossula, and three small 

 ones, representing a cross. The radiate arrangement of the septa somewhat irregular. 



Typ. sp., Hadrophyllum Orliyvyi, nob. 



11. Genus Combophyllum. 



Corallum presenting the general form of a Cyclolites. A single septal fossula. Septa 

 exsert, and regularly radiate. 



Typ. sp., Combophyllum osismorum, nob. 



Second Tribe— CYATHOPHYLLINjE. 



Septal apparatus regularly radiate, and uninterrupted, or equally divided into four 

 groups by four superficial septal fossula?. No true columella, but sometimes a spurious 

 one formed by the inner edge of the septa. 



