336 DISCOVERY REPORTS 



reputed B. italica, which must be contrasted with his figs. 79, 80 and 84 which show 

 the more usual fusing of septa ; this species is markedly compressed and the edge of its 

 calice arched by the exsert ends of septa I and II. 



Variation in the Genus Caryophyllia Lam.^ 



Corals of this genus may be regarded as central to the Turbinolidae, since species are 

 described in the reports of nearly every expedition that has indulged in deep-sea 

 collecting in whatever seas it has worked. The genus is hence cosmopolitan, and its 

 species can obviously withstand large ranges of temperature and salinity. Fossil forms 

 are widely distributed in suitable tertiary deposits, but have been described also from 

 the cretaceous. While the existing species are mainly inhabitants of waters deeper than 

 50 fm., which is about the limit of plant life, a few species occur up to the tidal areas. 



Now, all modern reports on corals and many other marine animals are based on a 

 supposition of gradual migration from shallow to deep seas. If this be the case, some 

 changes common to the skeletons of corals might be expected, the coralla perhaps 

 becoming thinner and more delicate while still quite suitable to the calmer, deeper and 

 colder waters. Examining living and fossil forms, I have not found such changes 

 within genera, perhaps owing to my having had too frequently to draw my own conclu- 

 sions as to the ecological conditions, which the living and now fossil corals had to face. 

 Indeed, when I study reports on the species of Caryophyllia, I find that my difficulties 

 as to the determination of specific characters and as to the range of variation in fossil 

 and living forms are precisely the same. The study of the oecological conditions of living 

 forms does not help much, for the information as to the nature of the bottom where they 

 lived, and of the temperature, salinity and movements of the overlying waters is scanty. 

 Furthermore, the study of shallow-water forms gives the impression that corals which 

 are detritus-feeders and possess no symbiotic algae, have a wide tolerance of fluctuation 

 in these. Using, as we must, the criteria of anatomy, especially that of living forms, it 

 would seem abundantly clear that many, perhaps most, fossil forms of Caryophyllia 

 still continue to exist to-day, in spite of the millions of generations that may have 

 intervened since their deposits were laid down. 



The skeleton of a coral gives no suggestion as to whether its polyp was adult, viz. 



1 The reader inter alia should consuh the "John Murray' Exp. Rep. v, no. 7, 1938 in which 55 out of 511 

 Caryophyllia, belonging to 6 species, are illustrated. Some remarks in this report (p. 169) are here more 

 carefully discussed after a renewed examination of the same specimens, helped by the specimens below and 

 many types and other supposed species in the British Museum. The Agassiz Museum, Harvard University, 

 has most generously sent me co-types of Pourtales' species. Among Duncan's types of corals, which Capt. 

 Totton has discovered to have been deposited in the British Museum under a different name from Duncan, 

 those from the 'Porcupine' Expedition [Trans. Zool. Sac. 1873 and 1878) include 10 "species" of Caryo- 

 phyllia each determined on a single specimen and 8 of these described as new. From the discussion below, 

 it will be clear that none of these can in my view be accepted. I have found Seguenza's plates of his 47 fossil 

 forms {Mem. Real. Acad. Set., Torino, ser. 11, 1864) and certain other palaeo-zoological literature most 

 illuminating; Ceratocyathus is a synonym. C. cyathus and profunda have been left in this Report as two 

 distinct species, because I have no series from the original locality of the former and no information as to the 

 environment from which my specimens were taken. 



