CORALS OF THE LONDON CLAY. 35 
S. Nysti,’ by its diminutive size, and by its low, very feebly-granulated septa. It is 
worthy of notice that S. discotdes is the only species of this genus that has as yet been 
found in the Eocene formations. We have seen four specimens of this Coral ; they were 
all met with at Haverstock Hill, and belong to the cabinet of Mr. Frederick Edwards. 
2. Genus BALANOPHYLLIA (p. lil). 
BALANOPHYLLIA DESMOPHYLLUM. ‘Tab. VI, figs. 1, 1a, 14, le. 
BaLANOPHYLLIA DESMOPHYLLUM, Milne Edwards and J. Haime, Monog. des Eupsammides, 
Ann. des Sc. Nat., 3° série, vol. x, p. 86, 1848. 
Corallum simple, adherent by a broad, incrustating basis, subturbinate, straight, rather 
elongated, and slightly compressed. Coste almost straight, closely set, and formed of one 
or more rows of irregular granule ; the primary and secondary ones much taller and much 
larger than the others, especially near the calice, and usually separated by five small ones, 
two of which begin to appear at about two thirds down the wall, whereas the others extend 
to the basis. Cadice slightly arched, and almost elliptical ; its long axis being to the short 
one in the proportion of 100: 160. Calicular fossula deep and narrow. Columella 
spongy, not highly developed, flat, and not prominent at the bottom of the calice. Septa 
forming five cycla, usually complete ; those of the fifth cyclum more developed than those 
of the third order, and becoming cemented together two by two beyond the inner edge of 
those of the fourth cyclum, and constituting thus in each half system two septal lamine, 
that in their turn unite between the inner edge of the tertiary septa and the columella. 
In the neighbourhood of the wall, the septa of the fifth cyclum that are situated next the 
primary and the secondary ones are cemented to them, and do not usually correspond to 
any distinct coste ; so that in each half system there are only five coste corresponding to 
seven septa. The large septa are terminated by an undivided edge, and are much more 
exsert than the others; all are thin, granulated laterally, very porous, and closely set ; 
those of the younger orders are delicately denticulated. Height of the corallum about 
1 We have given this name to a Stephanophyllia of the Antwerp Crag that we have seen in M. Nyst’s 
cabinet at Louvain, and had been referred by that author to the 8. imperialis (Coquilles et Polyp. foss. de 
Belgique, p. 633, tab. xlviii, fig. 17). This figure is pretty good, but does not show the small septa. Not 
having described it in our Monograph of Eupsammidee, we point out here its characteristic features. The 
under surface of Stephanophyllia Nystii, nob., is somewhat concave. The coste are of almost equal thick- 
ness, and do not appear distinctly composed of rows of granule ; they alternate with the well-developed septa, 
but correspond to rudimentary septa of the sixth eyclum; the younger ones are, as usual, united by their 
base to the elder ones, but this apparent bifurcation takes place only very near the centre of the corallum ; 
the intercostal furrows become gradually wider from the centre towards the circumference of the wall, and 
are bored with pores, that increase in size in the same manner. The calicular fossula is very deep. The 
septa are disposed in the same way as in S. discoides and S. elegans, but are much taller, thinner, and more 
angular; they are denticulated externally, and present on their lateral surfaces radiate strize, which resemble 
incomplete synapticule ; those of the last cyclum are very small. Diameter nearly an inch ; height, 53 lines. 
