PRESIDENT'S ADDRESS. 33 



such fauna has in its several parts one and the same relation to 

 others. Such is very far from being the case. 



The several tropical faunas are, for example, much more closely re 

 lated to one another than they are to the faunas along the same reach 

 of shore toward the arctic or antarctic regions. This relationship 

 is evinced more or less in every class and branch of animals, e. g., 

 the mammals, the fishes, the mollusks, the crustaceans, the worms, 

 the echinoderms, and the coelenterates. Consequently, the marine 

 faunas cannot be at all correlated with the primary realms or regions 

 of the globe. To such an extent does temperature determine the 

 distribution of life in the seas that even bathymetrical conditions 

 may be subordinated, and types of the shallow arctic and antarctic 

 seas represented in the cold deep sea under the equator. Some 

 forms almost identical reappear at the opposite poles. The infer 

 ence is irresistible that such types have migrated from common 

 ground, and may have originally developed either in the deep sea 

 and thence dispersed in opposite directions, or at one of the ex 

 tremes, and wandered thence over the bottom to their final resting 

 places. However this may be, a primary combination of the marine 

 faunas is most natural under the categories of Tropicalian, Arctalian, 

 and Notalian, while the temperate ones are rather the complexes of 

 the bounding regions. 



The views thus enunciated I propose now to reinforce, but it 

 may be expedient to give specific names to the northern and south 

 ern temperate regions. The primary marine regions or realms would, 

 therefore, be (i) the Arctalian, (2) the Pararctalian, (3) the Tropi 

 calian, (4) the Notalian, and (5) the Antarctalian. 



I. THE ARCTALIAN REALM. 



Arctalia, or the Arctic realm, for the sake of definition, might 

 be confined to the seas of the northern hemisphere, limited south 

 ward by the course of floating ice, which descends on the eastern 

 coast of North America as far as the Gulf of St. Lawrence. But so 

 few types are peculiar to that area, and so many of the character- 



