308 Bulletin American Museum of Natural History. [Vol. XXIV, 



hemisphere are separated from those of the southern hemisphere by a broad 

 belt of tropical and subtropical waters, covering not less than fifty degrees 

 of latitude; the species of the two hemispheres are not only restricted to 

 temperate latitudes, but are also absent from the Arctic and Antarctic seas. 

 On the other hand, the home of B. mysticetus is the icy waters of the Arctic 

 regions, it moving southward in winter on the closing of its summer haunts 

 by compact ice; it has also no representative in the Antarctic seas. The 

 species of Eubalcena are likewise migratory, moving toward warmer lati- 

 tudes with the approach of winter, and seeking colder latitudes with the 

 return of the warmer season. 



It is, indeed, physically impossible for the Right Whales of the north 

 temperate zone to visit the south temperate zone, or those of the latter to 

 visit the former. As shown by Lieut. H. M. Maury, 1 on evidence that has 

 never been refuted nor seriously contested, the torrid zone is "forbidden 

 ground" for the right whale; " . . . .and that it is physically as impossible 

 for him to cross the equator as it would be to cross a sea of flame. In short, 

 these researches show that there is a belt from two to three thousand miles 

 in breadth, and reaching from one side of the ocean to the other, in which 

 the right whales are never found" (/. c., p. 253). As this condition has 

 continued for ages, it is seemingly unnecessary to institute a detailed com- 

 parison between the Right Whale of the North Atlantic and its congeners 

 of the southern seas. Yet a comparatively recent English authority of note 

 (Flower, see antea, p. 301) has lumped them altogether as one species under 

 the name Balcena australis. This strange conservatism is still maintained 

 by British authors, as Lydekker, 2 Beddard 3 and Millais, 4 in their recent 

 popular accounts of these animals, in spite of the fact that all modern 

 zoogeographic , knowledge of the conditions which govern the geographic 

 distribution of animals is utterly opposed to such a conclusion. The case is 

 somewhat different with the Right Whale of the North Pacific, in respect to 

 its relation to its congener of the North Atlantic. They have their ranges 

 separated, not by tropical waters, but in part by the icy barrier of the Arctic 

 seas, and in part by immense continental areas; there is also evidence of 

 well-marked diversity in size and other characters, although the North 

 Pacific species is scientifically very little known. 



Nomenclature. As already shown (antea, p. 288), the Right W T hale of 

 the North Atlantic was provided with names by the early systematists, as 

 by Klein (1741), who called it Balwna glacialis, c. borealis, and by Brisson 

 (1756), who named it Balcena islandica, but as both of these authors are 



1 Sailing Directions, 7th ed., 1855, p. 253. 



2 Royal Natural History, Vol. Ill, sect. 5, 1895, p. 12. 



3 A Book of Whales, 1900, p. 133. 



4 Mammals of Great Britain and Ireland, Vol. Ill, 1906, pp. 224-231. 



