Page:Quarterly Journal of the Geological Society of London, vol. 27.djvu/587

 ter and Jeffreys's " Deep-sea Eesearches," Proc. Roy. Soc. Dec. 8, 1870) some Caryophyllioe were noticed which, possessed four incomplete cycles of septa, large and thick pali, and a columella made up of from two to six processes. They had glistening walls ; and the costae were subequal and principally visible superiorly. They were of course associated by me with the species cylindracea as varieties, the variation being in the size of the pali and the number of the columellar tigelles, both being very uncertain anatomical elements.

The dredging in 1095 fathoms off the coast of Portugal which yielded Pentacrinus Wyville-Thomsoni, Jeffreys, produced many corals ; and the series presented an eminently Cretaceous facies. The genus Bathycyathus, whose species Sowerbyi is so well known in the Upper Greensand, was represented there by numerous specimens of a species closely allied to that form.

A new species, Caryophyllia abyssorum, was also found, which is allied by its structural peculiarities to Caryophyllia Bowerbanki of the Gault ; and the specimen was discovered which is the subject of this communication.

The characteristics of Caryophyllia cylindracea, Reuss, sp., are shown in the specimen in a most unmistakable manner. The type is somewhat variable, and I have delineated some varieties in the " Supplement to the British Fossil Corals " (Pal. Soc.) ; but the specimen obtained from the greatest depth at which coral-life is as yet known to exist, belongs not to a variety, but to the original specific type.

The interest of this proof of the persistence of a deep-sea coral species is enhanced by its being associated with other corals which possess Cretaceous alliances. The group of forms has a decided Cretaceous facies.

When the discovery of Caryophyllia formosa, Pourtales, and that of the variety of Caryophyllia cylindracea, Reuss, sp., already alluded to, are considered in relation to the small group from the great depths, the homotaxis of part of the coral fauna of the Atlantic and that of the Cretaceous ocean about the same area becomes very remarkable.

Such Cretaceous genera as Trochosmilia, Parasmilia, Synhelia, and Diblasus are extinct ; but Amphihelia ramea, Mull, sp., represents the Synhelioe, and the position of the first two groups is now occupied by species of Paracyathi and Caryophyllioe, more elaborately constructed types, it is true, but adapted to the same bathymetrical zones and for the same destiny.

Why such species as Caryophyllia cylindracea should persist, and others, like Parasmilia centralis of the Chalk die out, is inexplicable, unless it is admitted that there is a law regulating the life- duration of species like that which restricts the years of the individual ; for the forms apparently throve under the same external conditions ; and if these have lasted so that the one species has persisted generation after generation, how upon any other theory can the other have become extinct ?

Considering that the generalization respecting the structural distinctions of deep-sea and reef-building corals must be accepted, it