GEOGRAPHICAL DISTRIBUTION OF CRUSTACEA. 15g5 



tutes a third province, the Platensian ; a fourth, from C. Antonio to 

 the south cape of the bay of Rio Negro, the Northern Patagonian, 

 five hundred miles long. A peculiar Grapsoid form of Rio Negro is the 

 Cyrtograpsus angulatus. The Hemigrapsus affinis is another species, 

 and this locality is the extreme outer limit of the genus Hemigrapsus, 

 as far as now known. Two peculiar Idotaeid forms occur in this 

 vicinity, having been taken by us from a fish: they are Cleantis 

 linearis, and Chcetilia ovata. The genus Serolis occurs farther south, 

 and does not appear to extend to Rio Negro. 



The subfrigid region, in its southern part at least, along Fuegia, 

 belongs properly to the Antarctic kingdom ; but the rest of the coast 

 may belong to another province, called the Southern Patagonian, which 

 may include also the coast of Western Patagonia south of the Arau- 

 canian Province. 



IT. AFRICO-EUROPEAN KINGDOM. 



The prominent differences in temperature between this kingdom 

 and the Occidental have been briefly pointed out. The most influen- 

 tial is the existence of a large temperate region, covering a conside- 

 rable part of the Mediterranean coasts, as well as a portion of the 

 western coast of Africa, with the Azores and Madeira; and also a 

 subtemperate on the coast of Portugal; both of which regions are 

 unrepresented on the coast of the United States. There are many 

 species peculiar to the Mediterranean ; and by their extension north, 

 they give a greater variety to the British seas than they probably 

 would otherwise have. 



On the African coast, we make Cape Agulhas the southern limit. 

 Table Bay, however, as is natural from its situation near the borders 

 between two great kingdoms, partakes of a middle character, yet 

 belongs more properly to the Atlantic Ocean. It affords the Oriental 

 species Platyonychus trimaculatus and Dromia kirsutissima ; but pro- 

 duces also a species of the Atlantic genus Homarus, and according to 

 M'Leay, the Sesarma reticulata of Say, besides four other species of 

 this genus. 



The genera peculiar to the Africo-European kingdom, and those 



common to it and the other kingdoms, are already mentioned on pages 



1548, 1550. 



392 



