DISTRIBUTION OF THE TERRICOLOUS OLIGOCHAETES 131 



subfamily Benhaminae and consists of two species of the genus Neogaster and 

 three of the genus Wegeneriella. These five species are found along the Atlantic 

 coast from Darien to the mouth of the Amazon River. The other four 

 species of these two genera are distributed along the Atlantic coast of Africa 

 from Cameroon up to Guinea. The American species of Neogaster are 

 extremely similar to the African ones; there are however, differences of 

 subgeneric rank between the species of Wegeneriella of the two opposite 

 shores. But one can say about these animals too, that the taxonomic distinc- 

 tion would not have developed if the species had been gathered on the same 

 continent: other genera of the subfamily are more heterogeneous than 

 Wegeneriella, and no one has bothered to subdivide them. 



Facts regarding the Oligochaetes of the Brazilian subregion can be sum- 

 marized in these words: the fauna has a very high degree of endemism, has 

 nothing in common with the Chilean-Patagonian subregion, and very little 

 relationship with the fauna of the Mexican and Antillean subregions; the 

 latter is probably due to relatively recent migrations. A certain relationship 

 between the earthworm fauna of the Brazilian subregion and the Palaeo- 

 tropical fauna is shown by the two genera Wegeneriella and Neogaster, 

 common to both, and the close resemblance between the American genus 

 Drilocrius and the African genus Alma. 



In the Chilean-Patagonian subregion, excluding the corner north of 

 Antofagasta and the region around the River Plata estuary, the Glossoscole- 

 cidae, Ocnerodrilinae, Benhaminae, and the genus Criodrilus disappear; that 

 is, all the taxonomic groups represented in the Brazilian subregion disappear, 

 whereas a new family appears, the Acanthodrilidae. 



The Chilean-Patagonian Acanthodrilidae include more than fifty species 

 belonging to five genera. The genus Yagansia is endemic, and its fifteen species 

 are distributed from the Tierra del Fuego up to Titicaca; two other genera 

 (Chilota and Parachilota) occur from Chile to South Africa over the islands 

 between the two continents: in the southern part of South America, on the 

 Falklands and in South Georgia, twenty-two species of Chilota and one 

 of Parachilota are endemic. The genus Microscolex has a similar but much 

 more extensive distribution, reaching the islands of Crozet and Kerguelen 

 south of Africa, and the islands of Macquarie, Auckland and Campbell south 

 of New Zealand; ten species of Microscolex are endemic to the southern 

 point of America. On the adjacent islands, no less than three are endemic on 

 the small island of Possession in the Crozet group (maps Figs. 3-5). 



The last genus, primitive as its name Eodrilus indicates, has a still greater 

 distribution and reaches Madagascar, New Zealand and Australia. Four 

 species of Eodrilus are endemic to the Chilean-Patagonian subregion. 



Thus, the tip of South America has four genera out of five in common with 

 South Africa; on the other hand, it does not have any genus, not even a 

 subfamily in common with the Brazilian subregion. T can add that the 



