A. H. CLARK : THE CRINOIDS OF THE INDIAN OCEAN. 



13 



related to C. (Bennettia) trichoptera of southern Australia, denoting a southern 

 sub-region distinct from that of the rest of the soutli-eastern coast. 



Beyond the east coast of Africa, the Mediterranean Sea and the coasts of 

 Europe as far north as Norway are inhabited by an extremely attenuated fauna 

 derived directly from the East Indian, characterized by Anledon (closely related 

 to Mastigonietra) and Leptometra (closely related to Psathyrometra) as well as by 

 Bathycrinus recuperatus , which is close to B. paradoxus. It is very curious that 

 this fauna should be characterized by forms all of whose nearest relatives are 

 found in the Bay of Bengal and are absent from the seas to the westward of Ceylon, 

 and it is equally strange that the fossil crinoid fauna of Europe, in so far as it is 

 comparable to the recent, should also agree with the fauna of the region of the 

 eastern part of the Bay of Bengal and the districts to the east and south. It 

 seems almost certain that the crinoid fauna of Europe has reached its present 

 location by passing north of India (or at least of southern India), avoiding the 

 present basin of the Arabian Sea and, originally almost as rich as that of the 

 East Indies to-day, has been gradually altered by the disappearance of such forms 

 as were unable to adapt themselves to the changing conditions, eventually 

 becoming reduced to its present dimensions. 



The south-east African fauna reappears in a slightly modified form off north- 

 western Africa and south-western Europe, extending thence westward to and 

 throughout the West Indies. Almost all of the genera have become somewhat 

 altered so that they are not quite the same as their East Indian progenitors, but 

 the alteration has never progressed far enough to obscure their affinities. The 

 West Indian genera with their East Indian ancestors are as follows : — 



East Indian Genus. 



Capillaster. 

 Comatella. 



Coniissia. 

 Coitiatula 



Corresponding West 

 Indian Genus. 



Comasteridag. 



Nemasler. 



Neocomatella. 

 ^ Leptoneinaster. 

 X Comatilia. 

 Comaclinia. 



StepJtanometra. 



Stephanometridse. 



Analcidomelra. 



Cosmiometra. 



ThalassometridcB. 



Stylometra. 



Pachylotnelra. } 

 Glyptometra. ^ 



Charitometridie. 



Crinornetra, 



