Fig. 80.—Cystiphyllum vesiculosum, showing a succession of cups produces by budding from the original coral. Of the natural size. Devonian, America and Europe. (Original.)
Fig. 81—Zaphrentis cornicula, of the natural size. Devonian, America. (Original.)
Fig. 82—Heliophyllum exiguum, viewed from in front and behind. Of the natural size. Devonian, Canada. (Original.) representatives of the Corals are still referable to the groups of the Rugosa and Tabulata. Amongst the Rugose group we find a vast number of simple "cup-corals," generally known by the quarrymen as "horns," from their shape. Of the many forms of these, the species of Cyathophyllum, Heliophyllum (fig. 82), Zaphrentis (fig. 81), and Cystiphyllum (fig. 80), are perhaps those most abundantly represented—none of these genera, however, except Heliophyllum, being peculiar to the Devonian period. There are also numerous compound Rugose corals, such as species of Eridophyllum, Diphyphyllum, Syringopora, Phillipsastrœa, and some of the forms of Cyathophyllum and Crepidophyllum (fig. 83). Some of these compound corals attain a very large size, and form of
Fig. 83.—Portion of a mass of Crepidophyllum Archiaci, of the natural size. Hamilton Formation, Canada. (After Billings.) themselves regular beds, which have an analogy, at any rate, with existing coral-reefs, though there are grounds for believing that these ancient types differed from the modern reef-builders in being inhabitants of deep water. The "Tabulate Corals" are hardly less abundant in the Devonian rocks than the Rugosa; and being invariably compound, they hardly yield to the latter in the dimensions of the aggregations which they sometimes form.
The commonest, and at the same time the largest, of these are the "honeycomb corals," forming the genus Favosites (figs. 84, 85), which derive both their vernacular and their technical names from their great likeness to masses of petrified honeycomb. The most abundant species are Favosites Gothlandica and F. Hemispherica, both here figured, which form masses sometimes not less than two or three feet in diameter. Whilst Favosites has acquired a popular name by its honey-combed appearance, the resemblance of Michelinia to a fossilised wasp's nest with the comb exposed is hardly less striking, and has earned for it a similar recognition from the non-scientific
