The Conditions in the Atlantic. 



In the Atlantic the conditions are, judged upon the basis 

 of the distribution of the crinoids, essentially the same as in 

 the Pacific, the Benguela current corresponding in every way 

 to the Humbolt current of the Pacific, and carrying the deep 

 water genera of South Africa to the latitude of the Bay of 

 Biscay, and the abyssal genera of the deeps of the antarctic 

 southeast of Africa to the deeps southwest of Iceland. The 

 return water reaches the antarctic along the coast of south- 

 eastern South America, coming up from beneath the Brazilian 

 current. 



The parallel between the conditions off the northwest coast 

 of Africa and those off southern California, and between the 

 conditions off the New England coast and those off the Kuril 

 Islands, has already been discussed. 



The Effect of Oceanographic Change in the Antarctic. 



The cold of the antarctic continent is undoubtedly very 

 greatly intensified by the broad band of abyssal water which 

 circulates about it, completely isolating it from the influence 

 of the drift from an equatorial current such as is responsible 

 for the mild climate of southern Alaska and of Europe. A most 

 impressive example of what the effect of abyssal water may 

 be is afforded by a visit to the central Kuril Islands in the 

 summer time. 



Since the present cold of the littoral portions of the antarctic 

 continent is very largely due to the influence of the abyssal 

 water which now circulates about it, it is evident that any 

 change in the past which interrupted this circulation of abyssal 

 water would have immediately resulted in a profound change 

 in the antarctic climate. 



Much has been written on the similarity of the fauna of 

 southern South America, New Zealand, and Tasmania and 



(285) 



