152 



THREE CRUISES OF THE "BLAKE. 



Oceans, — the survivors perhaps of an abyssal fauna, which, 

 thanks to the distributing agency of the equatorial currents, 

 extended, in mesozoic times, over the whole floor of the equa- 

 torial and a part of the temperate zones.^ 



1 Under favorable conditions, animals 

 having a wide geographical and geolog- 

 ical distribution have been found in prox- 

 imity to continental masses. The " Al- 

 batross " has dredged in deep water off 

 Chesapeake Bay many deep-sea types 



first known from the European tertiaries, 

 from the arctic and antarctic, from the 

 shores of Europe and of South America, 

 from the West Indies, and even from In- 

 dia and the Pacific Ocean. 



