DISTRIBUTION OF THE TERRICOLOUS OLIGOCHAETES 1 29 



European earthworms, but — a very curious fact — there we find five endemic 

 species of the genus P/utellus, of which genus the other endemic species are 

 found principally in AustraUa, Tasmania, and New Caledonia. The northern- 

 most species, which is also the only one endemic in Canada, is found on 

 Queen Charlotte Island. It is important to note that the genus Plutellus is 

 one of the very few that include forms that tolerate brackish and salt water. 



The earthworm fauna of the Neotropical region follows the classical 

 subdivisions quite well, with the difference, however, that the border line 

 between the Brazilian fauna and that of Chile-Patagonia runs farther south 

 than shown on maps drawn by most biogeographers (map. Fig. 2). It is 

 worth noting that along the same line the distribution of certain groups of 

 freshwater teleostei, amphibians, and terricolous molluscs comes to a halt. 



The peculiarity of the Neotropical Ohgochaete fauna lies in this fact: 

 the differences from subregion to subregion are very clear cut and do not 

 correspond to any existing geographical barriers. Nevertheless, whoever is 

 familiar with the biogeography of the OUgochaetes will not be surprised, 

 because a similar state of affairs occurs in many parts of the world. 



The Brazilian subregion is the one that has the most typical fauna, repre- 

 sented by an endemic family, Glossoscolecidae, and by members of two sub- 

 families of the Acanthodrilidae. 



The family Glossoscolecidae is made up of about 160 species belonging to 

 22 genera. The two most important centers of endemism of this family are 

 found in the high basin of the Amazon and in the low basin of the Parana/ 

 Uruguay. To the north the Glossoscolecidae extend into Mexican and 

 Antillean subregions, but it is important to note that there exist no endemic 

 genera, and the only two endemic species are found in Costa Rica and on the 

 Island of Barbados (the latter usually not included in the Antillean region). 

 Some Glossoscolecidae extend into the northwestern corner of the Chilean 

 subregion, formed by the Peruvian and Equadorian Andes: there the endemic 

 species are numerous. No species of Glossoscolecidae has ever been found 

 south of the fine that joins Bahia Blanca with Antofagasta. 



The Ocnerodrilinae are represented in the Brazilian subregion by four 

 genera of which five are endemic {Haplodrilus, Kern'oua, Queclniona, Paulistus, 

 Liodrilus) and one is found also in Lower CaUfornia. However, the taxonomy 

 of this genus (Eukerria) needs some amendment (cf. Gates, 1957), which may 

 lead to the two Californian species being separated. We find other genera of 

 this subfamily in central America. 



Another genus endemic in the Brazilian subregion is the aquatic Dri/ocrius, 

 of uncertain systematic position, but undoubtedly closely related to the 

 African genus Alma: the northernmost species, found in Costa Rica, {D. a/fari 

 Cognetti) has a morphology such that, if it had been found in Africa, it 

 would certainly have been ascribed to the genus Alma. 



The last Ohgochaete group of the Brazilian subregion belongs to the 



