526 PROFESSOR P. M. DUNCAN ON THE 
9. as no. 8, The primary and secondary septa are exsert. 
Surface of the wall sharply and finely granular, Costal striz near new calices, 
10, as no. 8. All the septa are exsert, and the costal strie are strong. 
11. as no. 10. The cost are cristiform near the calices. 
12. Columella well developed, 
The septa are in three cycles; and sometimes one of a higher order is present, 
Striz long and granular, often not continuous, 
Granules long. 
13. Surface like shagreen, otherwise as no, 12, 
It may be gleaned from this table that there are four groups:—l, with a plain wall- 
surface; 2, with a striated wall-surface ; 3, with exsert septa; 4, with exsert septa and 
long striations and sharp granules. 
Consequently the following diagnosis will include all the forms of Amphihelia, 
Genus AMPHIHELIA. 
Syn. Diphohelia. 
The corallum is bush-shaped; and the gemmation is alternate, marginal, and often 
double. ‘The wall increases in thickness at the lower part of the corallum, and often 
includes the formerly free corallites. The corallites often coalesce. The columella 
exists. ‘The septa are in six systems. ‘There are not many cycles of them. The 
ornamentation of the wall may be none, or the costal striz may exist. 
The corallites do not fill up from below. There is no dissepimental tissue. 
AMPHIHELIA OCULATA, Linneus, sp. (Plate XLV. figs. 1-3.) 
Branches irregular and coalescent. Calices distant and circular in outline, very 
prominent on the younger branches, and immersed in the wall-tissue lower down in 
the corallum, Columella moderately developed. Septa in six systems; and either 
three cycles are developed, or only two, the third being rudimentary. Septa unequal 
in the first case, and equal in the second. Wall-surface plain, and striated near the 
new calices. 
Variety «, with some septa slightly dentate. 
Variety 3, with the surface of the wall granular, 
Variety y, with exsert septa. 
AMPHIHELIA RAMEA, Miiller, sp. (Plate XLV. figs. 4-6, Plate XLVI. figs. 1-19, and 
Plate XLIV. figs. 1-3.) 
Syn. Amphihelia miocenica, Seguenza, 
atlantica, nobis. 
ornata, nobis. 
Diplohelia profunda, Pourtales. 
