CORALS OF THE UPPER CHALK. 45 
towards the basis, but presenting towards the calice slightly-marked coste, which are 
closely set, glabrous, or very delicately granulated, and almost equal in size.  Calice 
circular, or sometimes rather oval, shallow. Co/wmella moderately developed, not projecting 
in the centre of the calicalar fossula, composed of six or eight twisted, vertical processes, 
and terminated by an equal number of papillae. Sepéa forming four cycla, the last of 
which is in general incomplete ; the septa of the fourth and fifth orders not existing in one 
half of three of the systems or even of all six of these, so that the number of these 
radiate lamine is reduced to 42, or even to 36 ; sometimes, however, four of the systems 
are complete, and the number of the septa then amounts to 48. These septa are well 
developed, closely set, thin, but slightly granulated, rather exsert, and almost equal; the 
principal ones are, however, a little thicker than the others. ‘The pa/i are narrow, but 
very thick, prominent, aud terminated by a curved edge; they all correspond to the 
tertiary septa, and in the specimens where the fourth cyclum is complete, they exist in 
front of all the septa of the penultimate cyclum, and are therefore twelve in number ; but 
they are never so numerous when the fourth cyclum remains incomplete, and never 
correspond to tertiary septa that are not separated by septa of the fourth cyclum. As 
mentioned above, these latter septa are often wanting in one half of three of the systems, 
and in that case there are consequently no pali corresponding to the tertiary septa of these 
incomplete half systems, so that the number of pali is reduced to nine; two belonging to 
each of the three complete systems, and one to each of the mcomplete ones. The same 
rule also holds good when all the six systems are deficient of the septa of the fourth 
cyclum in one of their halves ; the tertiary septa of the complete halves are the only ones 
having corresponding pali, so that the number of these organs is only six. The height of 
the corallum varies between one inch and one inch and a half; in the tall specimens the 
diameter of the calice is about four lines ; in the short and broad ones it is sometimes five lines. 
This species is easily distinguished from the Cyathina Cyathus,‘ C. Smithii,’ and 
C. pseudoturbinolia, by its never having a fifth cyclum of septa. C. Guadulpensis* and 
C. arcuata’ differ from the above-described fossil by the existence of distinct costae down 
to the basis of the walls, and by the large size of the pali. C. devigata most resembles 
C. Koninckii,’ C. Bowerbankii,’ C. Debeyana, C. Brede, and C. cylindrica,” and it may 
! See our Monograph of Turbinolidee, Ann. des Se. Nat., 3™° série, vol. ix, p. 287, tab. iv, fig. 1. 
2 Loe. cit., p. 288. 3 Loe. cit., p. 289, tab. ix, fig. 1. 4 Loc. cit., p. 290. 
5 Loe. cit., p. 290. OMoes cit: 7p. 290: 7 Loc. cit., p. 292. 
5 The three last-mentioned species were not known to us when we published our Monograph of 
Turbinolidee, and in order to render the comparison between the 7’. /evigata and the rest of the genus more 
complete, it appears to us advisable to give a description of them here. 
CYATHINA CYLINDRICA, nob. Corallum fixed by a broad basis, regularly cylindrical, straight, and not 
very tall. Coste equal, flat, straight, closely set, not very broad, and very indistinct, especially towards 
the basis. Calice circular, having a thick edge, and the fossula rather shallow. Columella very small, and 
reduced to two or three small, almost indistinct, tubercles. Septa forming four complete cycla, very closely 
