232 STALK-EYED CEUSTACEA. 



elles des points de ressemblance multiplies." In 1852 Dana* published a 

 chart to illustrate the distribution of marine animals. On this chart the 

 waters of the globe are divided into five great circumterrestrial zones, whose 

 potent influence controls the distribution of marine life. The limits of these 

 zones are determined by isocrjmal lines, or lines of equal mean temperature 

 of the surface water during the coldest month of the year. The Torrid or 

 Equatorial Zone is bounded north and south by the isocryme of 68° F., — 

 the limit of reef-building corals. The North and South Temperate Zones are 

 included between the isocrymal lines of 68° and 35°, the North and South 

 Frigid or Polar Zones between the isocrymes of 35° and 26°. 



The relations existing between littoral Crustacea from similar latitudes 

 around the whole circuit of the globe make it clear that the primary ftiunal 

 divisions should be drawn with reference to the isocrymal lines. Yet Danaf 

 proceeds to base his fundamental faunal areas or " kingdoms " chiefly on 

 north and south lines running across the isocrymes, in accordance with the 

 general trend of the great continental shores. His Arctic and Antarctic 

 kingdoms alone are determined by latitude. Miers,:}; Henderson,§ and other 

 recent carcinologists have followed Dana's method. 



But other zoologists who have treated of the distribution of the littoral 

 marine fauna have based their primary divisions on the isothermal lines. 

 Thus, according to the Danish conchologist Murch,|| the marine fauna falls 



• United States Exploring Expedition, Vol. XIII., Pt. II., p. 1451. 

 + Op. c«V.,pp. 1530, 1554, etc. 



X Brachyura of the Challenger Expedition, p. xvii, 18S6. Dana's and Miers's primary faunal regions 

 may be readily compared as follows : — 



Dana. Miers. 



Kingdoms. Regions. 



Africo-European ... 3 Europe. ^ 



I W. Africa. V Atlantic. 



Occidental .... j E- America. ) 



X W. America Occidental. 



r E. Africa, \ 



Oriental J Indian Ocean. (.,>,, , , i, v 



^ Pacific coasts and islands, e.x- ^'Onental or Indo-Pacilic. 



\ cept W. America. ' 



( .\rctic shores, including Nor- ) 

 ■^■''^''"' ■< way, Iceland, Greenland, - Arctic or Boreal Cirrumpolar. 



(. Alaska, etc. ) 



( Antarctic sliores, including So. ) 

 Antarctic J Patagonia, So. New Zealand, V Antarctic or Austral Circumpolar. 



( etc. ) 



§ Anomura of the Challenger Expedition, p. 197, 1888. 

 II Malaknzoolog. Blatter, VI. 104, 1S60. 



