46 BRITISH FOSSIL CORALS. 
not be unworthy of notice that these five species are as yet the only representations of the 
genus Cyathina that have been met with in the Chalk Formation. At first sight they appear 
very similar, but by an attentive examination, constant and well-defined characteristic 
differences are found between all. In @. Koninchiz, the corallum is always shorter, and 
more regularly turbinate ; the pali are thicker, and the columella is reduced to two or three 
thick, twisted processes. In C. Bowerbankii, on the contrary, the pali are much thinner, 
and the surface of the walls appears granulous. C. cylindrica and C. Brede differ from 
it by a very peculiar character, which exists also m C@. Koninchkii, but which is not met with 
in any other species of the same genus, and is indeed quite an exception to the family of 
Turbinolidee, the pali being only six in number, although the four cycla of septa be com- 
plete, and corresponding to the septa of the antepenultimate cyclum, whereas they usually 
correspond to those of the penultimate cyclum. The thin, elongate form of C. Brede and 
the quite cylindrical form of C. cylindrica, will also help to distinguish them from C. /evigata, 
which differs also from C. Dedeyana, by the latter having a well-marked epithecal fold near 
the calice, a small columella, and thinner pali. 
Cyathina levigata is found in the Upper Chalk at Dinton, in Wiltshire ; specimens may 
be seen in the collections of the Geological Society, of Mr. Bowerbank, and of the Museum 
at Paris. 
set, and having stronger lateral granulations near the inner edge. The primary ones larger and rather 
thicker than the others, but differing very little from the secondary ones; the tertiary ones are thinner and 
smaller ; those of che fourth cyclum are distinct, but very small. Pali prominent, extremely thick, narrow, 
strongly granulated laterally, and corresponding to the secondary septa. Height of the corallum about six 
lines ; diameter of the calice three lines. Fossil from the Chalk of St. Peter’s Mountain, at Maestricht ; speci- 
mens exist in the Museum of Natural History of Paris, and in the Tylerian Museum at Haarlem. 
Cyatuina Breps®, nobis. This fossil corallum, which we dedicate to Professor Van Breda, is adherent 
by a rather broad basis, contracted immediately above, elongate, slender, much bent, and cylindrical towards 
its upper part. The costee are not well marked, and the walls are almost smooth, but present sometimes 
slight horizontal folds. Calice cireular; fossula shallow. Columella but little developed, and sometimes 
reduced to a single twisted process. Septa forming four complete cycla; but those of the last eyclum 
rudimentary though distinct; the primary ones rather thick, especially towards the inner edge; the 
secondary ones resembling those of the first cyclum, but rather narrower; the others very thin. The 
granulations on the sides of the septa are conical, and very prominent. The pali corresponding to the 
secondary septa, well developed, prominent, narrow, and appearing very thick, because they are flexuous. 
Height, seven or eight lines; diameter of the calice, two lines and a half. This species is also found in the 
fossil state in the Chalk of St. Peter’s Mountain, at Maestricht; specimens exist in the collections of MM. 
Van Riemsdyck and Bosquet, at Maestricht ; of M. Van Breda, at Haarlem; and of the Museum at Paris. 
Cyatnina Depeyana nob. Corallum cylindrical, elongate, slightly curved, and presenting near the 
calicular margin a small but well-marked circular band, representing an incomplete epitheca. Calice 
circular ; fossula not deep. Septa unequal, closely set, somewhat exsert, rather thick externally, but thin 
towards the inner edge. and forming four complete cycla; the secondary ones almost as large as those of 
the first cyclum. Pali rather narrow, and not very thick. Height, one inch; diameter of the calice, three 
lines ; depth of the fossula, one line. Fossil from the Chalk of Aix-la-Chapelle, discovered by M. Debay. 
