1871.] DUNCAN PERSISTENCE OF CARYOPHYLLIA CyilNDBACEA. 437 



ter and Jeffrej's's "Deep-sea Eesearches," Proc. Hoy. See. Dec. 8, 

 1870) some Caryophyllice were noticed which possessed four incom- 

 plete 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 

 Pentacrhius Wyville-Thomsoni, Jeffreys, produced many corals ; and 

 the series presented an eminently Cretaceous facies. The genus Ba- 

 thycyathus, whose species Soiverbyi 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 BoiverbanM 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. See.) ; but the spe- 

 cimen 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 Caryojyhyllia formosa, Pourtales, and that 

 of the variety of Caryophyllia cylindracea, Reuss, sp., already alluded 

 to, are considered in relation to the smaU 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 

 Biblasus are extinct ; but Amphihelia ramea, Miill. sp., represents 

 the Synhelice, and the position of the first two groups is now occupied 

 by species of Paracyathi and Caryophyllice, more elaborately con- 

 structed 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 gene- 

 ration after generation, how upon any other theory can the other 

 have become extinct ? 



Considering that the generalization respecting the structural dis- 

 tinctions of deep-sea and reef-building corals must be accepted, it 



