xii BRITISH FOSSIL CORALS. 



chamber, and containing neither dissepiments, as in the Astreidse, nor synapticulse, as in 

 the Fungidse. Walls thin, lamellar, and imperforated. Septa highly developed, simple, 

 compact, in general regularly granulated on each side, and never denticulated or lobulated at 

 their apex. Costa in general well marked and straight. No ccenenchyma in the compound 

 Polypidoms. 



First Tribe— CYATHININ^E. 



Milne Edwards and J. Haime, loc. cit., p. 289, 1848. 

 Calicule presenting one or more rows of pali, placed between the columella and the septa. 



§ 1. A single coronet of pali. 



1. Genus Cyathina. 



Caryophyllia, Stokes. Zool. Journ., vol. iii, p. 486, 1828. 



Cyathina, Ehrenberg. Corall. des Rothen Meeres, p. 76, 1834 ; Milne Edwards and J. Haime, op. cit., p. 285. 



Corallum simple, never gemmiparous, subturbinate and adherent. Calice circular or 

 nearly so, with a broad but not very deep central fossula. Columella fasciculate, composed 

 of a certain number (3 to 20) of vertical, narrow, and twisted lamellar processes, and termi- 

 nated by a convex, crispate surface. Pali broad, entire, free in a considerable part of their 

 length, and equally developed. Septa straight, broad, exsert, and forming six systems, 

 which are in general unequally developed, and become in appearance much more numerous. 

 Costos straight, slightly prominent near the calice, more or less obsolete lower down, 

 delicately granulated, and never armed with tubercles, crests, or spines. 



Typical species, Cyathina cyathus, Ehrenb., loc. cit. ; Milne Edwards and J. Haime, Ann. des Sc. Nat., 

 3 me serie, torn, ix, tab. iv, fig. 1. 



2. Genus Ccenocyathus. 



Milne Edwards and J. Haime, Ann. des Sc. Nat., 3 me serie, torn, ix, p. 297, 1848. 



Corallum composite and adherent ; the corallites sub-cylindrical, rather tall, segregate 

 (united near their basis, but free in the greatest part of their length), and not grouped in 

 rows. Calice circular; fossula not very deep. Columella composed of a few twisted, 

 lamellar, vertical processes. Pali entire, equidistant from the centre, and similar in size. 

 Septa rather broad, not projecting much above the walls, and forming four cycla, the 

 last of which is incomplete in one of the six systems. Costa distinct near the calice 

 only, straight, flat, broad, and delicately granulated. 



These Corals have great affinity to Cyathina, from which they differ principally by 



their gemmiparous mode of multiplication, and the permanent union of the young to the 



parent. 



Typ. sp., Ccenocyathus cylindricus, Milne Edw. and J. Haime, loc. cit., tab. ix, fig. 8. 



