298 PROCEEDINGS OF THE AMERICAN ACADEMY 



to the northwest about latitude 65°, and, trending with the coast, 

 formed, with another volcanic series of mountains, the backbone of the 

 Alaskan Peninsula and the Aleutian Islands. Instead of a confused 

 mixture of eastern, western, and Asiatic forms in the bird-fauna, it was 

 discovered that the latter was mostly composed of Eastern and Cana- 

 dian forms, which passed westward north of the mountain wall of the 

 Alaskan Range, and, throwing out the water-birds, contained very few 

 representatives of the West American avi-fauna ; fewer, indeed, in 

 number, than those of the Eastern type, which encroached on the west- 

 ern district south of the mountains along the coast. 



The distribution of the marine animals presented some phenomena 

 of great interest not yet fully worked out or explained. The " line of 

 floating ice " in Bering Sea passes between St. Matthew and the Priby- 

 loff group of islands, and appears to form an invisible but very distinct 

 line of demarcation, north of which the fur-seal, cod, and marine in- 

 vertebrates, typical of the temperate west-coast fauna, do not pass ; 

 while the white bear, certain fish, and all the strictly arctic inverte- 

 brate marine forms, keep as constantly to the north as the others do to 

 the south side of the line. 



The glimpses thus obtained of a marine fauna of wonderful richness, 

 and the great interest attaching to the deep-sea dredgings, inaugurated 

 by the U. S. Coast Survey, and since carried on by Carpenter and Wal- 

 lich, Jeffreys, Sars, MacAndrew, and others, have impressed me with 

 a desire to attempt a further exploration of the marine fauna of these 

 regions. They are of special interest, from the fact that the researches 

 of Carpenter, Adams, MacAndrew, and Forbes have shown an identity 

 of species common to our northwest coast, Japan, the JEgean Sea, 

 and, finally, the Red Sea ; and the phenomena revealed by the dredge 

 have a very important bearing not only on the distribution of animals, 

 but on geology and the serial succession of animal life in time. 



I hardly feel justified at present in saying more than that I have 

 strong hopes that such explorations will not long be delayed, and that 

 they will probably be prosecuted in connection with a hydrographic 

 survey of the little-known coasts and islands of that portion of the con- 

 tinent ; a survey which will, if successful, bring forth results of inter- 

 est and value not only to the naturalist, but to the physicist, geologist, 

 and those engaged in purely commercial pursuits. 



Remarks on this communication were made by the President 

 and Professor B. Peirce. 



