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 fact that no Adelopomae inhabit any part of 
Asia or North America. 
Professor Stoll,£ who made a special study of the mites of 
* Ivobelt, W., “Cyclophoridae.” 
t Andreae, A., “ Binnenconchylienfauna von Oppeln,” II., p. 23. 
X Stoll, 0., “ Zoogeographie d. Wirbellosen,” pp. 19—20. 
L.A. 
S 
