xil BRITISH FOSSIL CORALS. 
chamber, and contaming neither dissepiments, as in the Astreidae, nor synapticule, as in 
the Fungide. 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. Coste in general well marked and straight. | No ecenenchyma in the compound 
Polypidoms. 
First Tribe—CYATHININ AS. 
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 simgle coronet of pali. 
1. Genus CYATHINA. 
Caryophyllia, Stokes. Zool. Journ., vol. ii, 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. Co/wmella fasciculate, composed 
of a certain number (3 to 20) of vertical, narrow, and twisted lamellar processes, and termi- 
nated by a convex, crispate surface. Padi 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. 
Coste straight, slightly promiment 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™° série, tom. ix, tab. iv, fig. 1. 
2. Genus C@NOCYATHUS. 
Milne Edwards and J. Haime, Ann. des Se. Nat., 3™° serie, tom. ix, p. 297, 1848. 
Corallum composite and adherent ; the coradlites 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. Pa/i 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 mcomplete in one of the six systems. Coste distmct 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., Ceenocyathus cylindricus, Milne Edw. and J. Haime, loc. cit., tab. ix, fig. 8. 
