illustrating the Distribution of Marine Animals. 22 J 



meeting of the isocrymes of 74° and 68°. At the south ex- 

 tremity of Africa, on the west coast of Asia, there are ap- 

 proximations to the same fact. Cape Cod, the south-east 

 cape of New England, is a marked point in zoological geo- 

 graphy, and the termination of the isocryme of 44° F. ; and 

 the North Cape of the La Plata, inside of Maldonado, is 

 another. 



We proceed to give an enumeration of the several Zoolo- 

 gical Provinces, to which we are led by the temperature re- 

 gions adopted. It should be again observed, that the iso- 

 cryme of 68° is the grand boundary of coral reefs, and of the 

 larger part of the zoological life connected with them, and 

 that the Torrid Zone and Coral-reef Zone of oceanic tempe- 

 rature are synonymous terms. 



We mention also the extent of the Provinces ; and it will 

 be found, that although seemingly numerous, few of them are 

 under 500 miles in length, while some are full 4000 miles. 



For zoological reasons which are explained in another 

 place,* and which may be the subject of another communi- 

 cation to this Journal, we adopt for Marine Zoological Geo- 

 graphy, three grand divisions of the coasts of the globe. 

 1. The American or Occidental, including East and West 

 America ; 2. The Africo-European, including the coasts of 

 Europe and Western Africa ; and, 3. The Oriental, including 

 the coasts of Eastern Africa, East Indies, Eastern and South- 

 ern Asia, and Pacific. Besides these, there are the Arctic 

 and Antarctic Kingdoms, including the coasts of the frigid 

 zones, and in some places, as Fuegia, those of the ex- 

 treme temperate zone. We add here, only in general terms, 

 that there is a remarkable similarity in the genera of East- 

 ern and Western America, and an identity of some few spe- 

 cies ; that the coast of Europe and Eastern Africa widely dif- 

 fer in Crustacea from either the American or Oriental ; that 

 the species of the Oriental division have a great similarity 

 in genera, and that numerous species of Crustacea of East- 

 ern Africa are identical with those of the Pacific. We pass 

 by, for the present, the details on these points. 



* The author's Report on Crustacea. 

 VOL. LVI. NO. CXII. — APRIL 1854. Q 



