INTRODUCTION. Ixvii 
7. Genus Hatta. 
Corallum tall, turbmate. Sepa highly developed, and extending to the centre of the 
tabule. 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 suleatum ; Caninia sulcata, D’Orbigny, Prod. de Paléont., vol. i, p. 105. 
9. Genus TROoCHOPHYLLUM. 
Corallum simple, trochoid. Cadice 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 Orbignyi, 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—CYATHOPHYLLIN &. 
Septal apparatus regularly radiate, and uninterrupted, or equally divided into four 
groups by four superficial septal fossula. No true colwmed/a, but sometimes a spurious 
one formed by the inner edge of the septa. 
