There are twenty-eight septa, which are stout toward their outer margins, and become attenuated, and extend inwards to the centre of the visceral chamber. The fossula is large, and extends into the centre of the calicular cavity, and situated on the ventral or concave side of the corallum. One of the septa, of shorter length than the others, is included in it.

Height of corallum, 10 lines; diameter of calice, 6 lines.

Position and Locality.-Found in Auchenskeoch Quarry, Dalry, Ayrshire, in a band of shale about 12 feet above the lowest bed of carboniferous limestone in that district.

This species is distinguished from all the other species of the genus by the prominent longitudinal ridges on the epitheca, and by the presence of numerous elongated tubercles along the crown of the ridges. It is closely allied to Zaphrentis Koninckii (E. and H.); it, however, differs from that species by the presence of a larger fossula, and the nodular aspect of its external wall.

In external aspect it resembles "Amplexus modulosus." Being, however, satisfied that in all cases it is absolutely necessary to cut transversely fossil corals before we can determine either genera or species, I had this interesting little coral cut, and found that it possessed characters sufficiently distinct to warrant me in adding it as a new species to the genus Zaphrentis, and I have great pleasure in naming it in honour of its discoverer, Mr. John Smith, Eglinton Iron-works, Kilwinning, to whom I offer my thanks for allowing me to add it to the list of this interesting genus.

EXPLANATION OF PLATES.

PLATE I.

Fig. 1.-Centrephyllum subcentricum, a transverse section, natural size. Lower carboniferous, Thirdpart, Beith, Ayrshire.

IA.-A longitudinal section of the same, natural size. The letter B
points to a small portion of the interlamellar stria exposed
where the corallum was curved. In cutting the longitudinal
section at the curved part, the section passes diagonally between
the lamella of the septa, and thus exposes the stria.
2.-Centrephyllum bicentricum, showing the floor of the calice and the
arrangement of the lamellæ. Lower carboniferous, Thirdpart,
Beith, Ayrshire.

2A.-A transverse section of the same, natural size.

2B.-A longitudinal section of the same, natural size, the interlamellar stria and the cut ends of the inner ends of the septa are exposed at the curved portions of the corallum.

3.-Centrephyllum trilamellum, a transverse section, natural size.
Lower carboniferous, Charleston, Fifeshire.

4.-Centrephyllum hexalamellum, showing the floor of the calice, the
everted periphery, and the arrangement of the centre of its floor.
Lower carboniferous, Brockley, Lesmahagow, Lanarkshire.
4A.-A transverse section of the same, natural size.

5.-Centrephyllum granulatum, natural size. Lower carboniferous,
Thirdpart, Beith, Ayrshire.

6.-Clisiophyllum, natural size. Lower carboniferous, Broadstone, Beith, Ayrshire.

PLATE II.

Fig. 1.-Centrephyllum cylindratum, showing in outline the size of the corallum and the calice at the superior extremity. Lower carboniferous, Gateside, Beith, Ayrshire.

1A. A transverse section of the same, natural size. This section is
cut 1 inch from the crown of the corallum.

IB.-A longitudinal section of the same, and cut 3 inches from
the superior extremity, natural size, showing the interla
mellar stria, the cut ends of the septa and the interlamellar
stria passing diagonally between the lamella of the septa.
lc.-A transverse section of the same, natural size. Cut 1 inch from
the inferior extremity of the corallum.

2.-Centrephyllum quadralamellum, a tranverse section, natural size.
Lower carboniferous, Langside, Beith, Ayrshire.

3.-Centrephyllum pentalamellum, a transverse section, natural size.
Lower carboniferous, Langside, Beith, Ayrshire.
4.-Centrephyllum nudaphyllum represents the external aspect of this
remarkable corallum. It is much crushed and broken in the
centre. Lower carboniferous, Charleston, Fifeshire.