EUROPEANS IN CENTRAL AMERICA 257 



larger genus Amphicyclotus has its centre of dispersal in 

 Colombia and Ecuador. From there it pressed eastward 

 through Venezuela into Guiana and across Trinidad to the 

 island of Martinique, which must have been connected for 

 some time with the southern mainland. In Central America 

 the genus has a discontinuous range. A few species occur 

 in Costa Rica, Guatemala and southern Mexico. Not a single 

 species is known from the Greater Antilles. 



There is one very important feature in the fauna of Central 

 America which I have scarcely dwelt on as yet, and that is its 

 affinity with Europe. It is not at all striking. Yet it does 

 exist. The large group Diplommatininae belonging to the 

 family Cyclophoridae is almost entirely confined to southern 

 Asia, the Pacific islands and Australia.* Only the single 

 genus Adelopoma occurs in America. Its wide and extremely 

 discontinuous range in the New World marks it as a very 

 ancient immigrant, for it is likewise known from Argentina, 

 Peru, Guatemala and Trinidad. Now the Guatemalan species 

 (Adelopoma stolli) has its nearest relation in the Miocene 

 beds of Oppeln in Silesia, for Professor Andreae f informs 

 us that the fossil Adelopoma martensi occurring in these 

 deposits is scarcely distinguishable from a species inhabit- 

 ing Central America. Our first impulse on hearing of 

 this extraordinary discovery is to attribute it to con- 

 vergence or even misidentification. But the identifica- 

 tion has been confirmed by Professor Boettger, one of the 

 most eminent of European specialists, while Adelopoma 

 stolli is not by any means the only Central American 

 land mollusk that possesses European affinities. Many other 

 instances will be alluded to in the next chapter (p. 265). 

 Those who wish to interpret all cases of intimate relationship 

 between American and European forms, as arising from a 

 remote migration across a hypothetical Bering Strait land 

 bridge, will find it difficult to reconcile this particular occur- 

 rence with the fa/ct that no Adelopomae inhabit any part of 

 Asia or North America. 



Professor Stoll,J who made a special study of the mites of 



* Kobelt, W., " Cyclophoridae." 



t Andreae, A., " Binnenconchylienfauna von Oppeln," II., p. 23. 



j Stoll, 0., " Zoogeographie d. Wirbellosen," pp. 1920. 



L.A. S 



