31 



the British admiralty, and in the Encyclopaedia Britannica*. 

 Nevertheless, charts based upon the latest observations of the num 

 erous explorations that have been made within the past decade and 

 especially adapted for the zoologist are great desiderata, and it is 

 hoped that our own Coast Survey and Hydrographic Office, or the 

 United States Fish Commission, may supply the want. 



Prof. Dana f recognized nine "regions" or categories of tem 

 perature, segregated under three " zones," and all these, except the 

 equatorial, were duplicated in the respective hemispheres, thus : 



I. TORRID OR CORAL-REEF ZONE. 



Regions. Isocrymal limits. 



1. Supertorrid, [Eq.] 80 F. to 80 F. 



2. Torrid, [Eq.] 80 to 74 



3. Subtorrid, [N., S.] 74 to 68 



II. TEMPERATE ZONE. 



1. Warm Temperate, [N., S.] 68 to 62 



2. Temperate, [N., S.] 62 to 56 



3. Subtemperate, [N., S.] 56 to 50 



4. Cold Temperate, [N., S.] 50 to 44 



5. Subfrigid, [N., S.] 44 to 35 



III. FRIGID ZONE. 



i. Frigid, [N., S.] 35 to 26 



It is suggested that an additional " region, called the Polar, may 

 be added, if it should be found that the distribution of species living 

 in the frigid zone requires it, There are organisms that occur in 

 the ice and snow itself of the Polar regions ; but these should be 



* The Wind and Current Charts for the Pacific, Atlantic, and Indian Oceans, 

 giving the isothermals of February for the northern hemisphere, and of August for 

 the southern, published in 1872, will be found the most useful. These have been 

 essentially reproduced in the article " Meteorology " of the Encyclopaedia Brit- 

 annica, vol. 16, p. 133, 1883. 



f DANA, op. cit., p. 157. 



