DEEP-SEA FA.UN.E OF THE WEST INDIES. 49 



Astrocaenia. Orbicella. Stylophora. 



Ca^loria. Cyphasti'aja. Siderastrasa. 



Diploria. Goniastrasa. Agaricia. 



Mivandrina. Solenastrsea. Porites. 



Favia. Plesiastrasa. 



It will be noticed that there are less deep-sea genera common to the ter- 

 tiary and living fliunaj of the West Indies than there are common to the 

 European tertiary and the living AVest Indian ones. This might be thought 

 to be due to smaller changes of level in the latter region than in Europe. 

 But if we assume, as we can with great probability, that the West Indian 

 extinct genera belonging to the families of Turbinolidoj and Parasmilida?, 

 which are quite numerous, were deep-sea corals, this reasoning fails, and we 

 are led to the conclusion that there has really been a great change in the 

 West Indian deep-sea fauna ; or, in other words, that the tertiary deep-sea 

 fiiuna of Europe has, as it were, migrated westward and maintained itself, 

 whilst the greater part of the cotemporaneous forms of the West Indian 

 deep sea have become extinct. 



Cambridge, February, 1874. 



