244 GEOGRAPHICAL AND GEOLOGICAL DISTRIBUTION. 



cocyathus, Parasmilia, Lophohelia, &c.) in the Mesozoic series. No 

 Palaeozoic genera are represented, and, if we excejit the Cyatlion- 

 axidse, apparently not even any of the distinctive families. A few 

 of the forms have been identified with Tertiary species, as Delto- 

 cyathus Italicus, Caryophyllia communis (Sicily), and, among others, 

 possibly one or more sjiecies of Flabellum and Stephano^ihylila. 

 Caryophyllia cylindracea, a w^ll-known European Cretaceous spe- 

 cies, has been dredged in eleven hundred fathoms Avater oil the 

 coast of Portugal, in associations with other forms of an equally 

 ancient aspect.** One species of Stejihanophyllia (S. complicata, 

 from the Ki Islands), although having its nearest ally in the S. dis- 

 coides from the London Clay (Eocene), is, remarkably enough, in 

 certain peculiarities of structure, most intimately related to a form 

 from the Jurassic formation of Germany (S. florealis). At the pres- 

 ent day, as far as is known, the genus survives only in a remote 

 spot of the East Indies, completely severed from its former Euro- 

 pean habitat. Desmophyllum ingens, from the fjords of Western 

 Patagonia, appears to be specifically identical with an undetermined 

 species from the Quaternary deposits of Messina, Sicily. 



It will be manifest, from what has preceded, that the modern 

 distribution of the deep-sea corals affords little satisfactory evidence 

 as to the special conditions — light, temperature, or depth — which 

 affect the development of this class of animals. Indeed, it would 

 appear at first sight as though none of these conditions were di- 

 rectly involved in the distribution of the group as a whole, or of its 

 individual members. The great bathymetrical range of many, or 

 the majority, of the forms, from the surface waters of a mild tem- 

 perature to the water of icy coldness, clearly proves the ready adapt- 

 ability of these organisms to extremes of temperature, or, what 

 might also be true, the want of appreciation, on their part, of ther- 

 mometric conditions. It is to be noted as a remarkable circumstance 

 in this connection, seeing through what an extensive range of tem- 

 perature their vertical distribution extends, that so few of the forms 

 penetrate within shallow water, or water of less than fifty fathoms. 

 Professor Fuchs has attempted to explain this anomaly on the as- 

 sumption that these, as well as other strictly deep-sea organism"?, 

 were animals of darkness, and that they rarely penetrated within 

 the zone of light-penetration. But it may be questioned, as has 

 already been done when treating of the life of the sea, whether the 



