16 BRITISH FOSSIL CORALS. 
occupy 2 line in length. No rudiments of a fourth cyclum of coste, and a well-marked 
depression in calicular edge of the wall, corresponding to each of the intercostal spaces. 
Calice with a very narrow, but rather deep fossula. Colwmella compressed, arched at the 
apex, granulated on the surface, reaching in general to the same height as the septa, or 
even higher, and presenting, in the part where it begins to become isolated, six vertical 
striae, which are in continuity with the inner edge of the six primary septa; rather lower 
down, the columella is shghtly contracted, and a vertical section of the corallum (fig. 14) 
shows that its tissue is compact, and that towards the bottom of the visceral chamber it 
becomes united with the septa, so as to form a solid mass. Sepfa thin, unequal, very 
exsert, having their upper edge strongly arched near the outer margin, but concave near 
the centre of the calice, slightly granulated laterally, and forming three cycla; those of the 
first and the second cycla nearly of the same height, but the secondary ones much broader 
at the apex than the primary ones, and not extending so far up the columella. The 
tertiary septa much narrower and shorter than the older ones; very thin towards their 
inner edge, and cemented to the primary septa, as in the preceding species (fig. 14). 
Interseptal loculi large. Height of the corallum about four lines. Diameter of the calice, 
two lines and one third. The form and the proportions not differmg in the young and 
in the adult specimens. 
Turbinolia Dixonii is the largest known species of the genus, but 7. dispar and 
7. Prestwichii are almost of the same size. This species is very closely allied to 7! sulcata, 
from which it differs principally by its form (rather more inflated near the calice), by its 
compressed columella, by its septa being more exsert, and its costae more projecting and 
more distant. The breadth of the intercostal furrows distinguishes both 7. Divoni and 
T. suleata from T. Prestwichii, T. minor, T. firma, T. pharetra, T. Nystiana, and 
T. Bowerbankit. The existence of only three cycla of costa does not allow of its being 
confounded with 7! Predericiana, T. dispar, and T. costata, and, finally, 7. humilis is 
easily distinguished from it by its cylindroid form, non-compressed columella, and 
glabrous septa. 
Turbinolia Divxonii is a fossil very abundant in the London Clay at Bracklesham Bay, 
and has probably been confounded with 7. swlcata by Mr. Fleming, and some other 
geologists, who mention the latter as being found in that locality, where it appears to be 
very rare. In Mr. Dixon’s work, now passing through the press, Mr. Lonsdale has also 
described it as a variety of the Z. sw/cata of Lamarck. 
The specimens, the examination of which has enabled us to recognise this new species, 
were given to us by Mr. Dixon and by Mr. Frederick Edwards. 
3. TursinoniA Bowrrpanku. ‘Tab. II, figs. 3, 3a, 36. 
Corallum almost conical, rather short. Coste not very prominent ; those of the first 
two cycla inflated near the basis ; the tertiary ones beginning at less than a quarter of the 
distance from the basis to the calicular edge of the wall; slight rudiments of a fourth 
