380 ORTMANN — DISTRIBUTION OF DECAPODS [Aprils, 



Gondwana Land. It comprises the Brazilian mass (including 

 Guiana) and tropical Africa with the Lemurian Peninsula (Mada- 

 gascar-India). This continent corresponds, generally, to Neu- 

 mayr's Jurassic Brazilo- Ethiopian continent, but comprises a 

 smaller part of South America (also, for Jurassic times, the section 

 of South America that entered it, according to Neumayr, is too 

 large). It agrees to a certain degree with what v. Ihering has 

 called Archhelenis, although it is larger, and it may be permitted 

 in this sense to modify the conception of Archhelenis. 



Thus in Lower Cretaceous times we have the following four con- 

 tinental masses : Sino-Australia, Nearctica, Antillia, Archhelenis, 

 which were mutually isolated. Besides, there were smaller islands, 

 chiefly in the region of present Europe. 



b. Upper Cretaceous. (See Fig. 6, p. 381.) 



The following changes took place : 



Sino-Australia was divided into a Sinic (Asiatic) and an Australian 

 part, the latter comprising Australia and Antarctica. 



The Sinic section of Sino-Australia became united, across Bering 

 Sea, with the western part of Nearctica. 



The western part of Nearctica was separated from the eastern. 



The western part of 'Nearctica became united with Antillia. 



Guiana became united with Antillia and separated from the 

 Brazilian mass. 



Brazil became disconnected from Africa. 



The Lemurian bridge was connected with the Sinic continent. 



The result of this is : 



I. An irregular ring of land around the earth, which, generally, 

 encircles it in the direction of the equator, but curving far to the 

 north in the region of the Pacific Ocean. This ring, beginning at 

 the Sinic land, goes across Bering Sea to western North America, 

 thence to Antillia, Guiana, Africa and the Lemurian land-bridge, 

 which latter completes it by its union with the Sinic land. We 

 may call this ring-shaped continent Mesozonia. 



Aside from Mesozonia we have, separated from it, the following 

 continental masses : 



II. Upper Cretaceous Nearctica. Smaller than the Lower 

 Cretaceous continent of the same name, since its western part is 

 cut off and enters Mesozonia. 



