132 P. OMODEO 



subregion of Cape of Good Hope shares with the Chilean-Patagonian sub- 

 region four out of seven genera, but has no genus and only one of its two sub- 

 families in common with the rest of the African continent. Because of this, an 

 oligochaetologist could mistake a collection from Patagonia for one from the 

 Cape of Good Hope, but he could never confuse a collection of Chilean 

 earthworms with one from Brazil. 



To complete the picture, I want to add some information regarding the 

 biogeography of an austral family of limicolous Oligochaeta, the Phreodrili- 

 dae, sub-divided into four genera, Hesperodrilus, Phreodrilus, Gondwanae- 

 drilus, and Phreodriloides. The first genus has endemic species spread through 

 Chile, the Tierra del Fuego, the islands of South Georgia, Crozet, Kerguelen, 

 and Campbell, New South Wales, and Ceylon. The genus Phreodrilus has 

 endemic species in New Zealand, South Africa, the Tierra del Fuego, and the 

 Falklands. Gondwanaedrilus and Phreodrilus are endemic, respectively, in 

 South Africa and New South Wales (map. Fig. 6). It is notable that two 

 families of fish, Haphochitonidae and Galaxidae, and one family of crayfish, 

 Parastacidae, have distributions almost identical with those of the Phreo- 

 drilidae and the Acanthodrilinae (cf. Joleaud, 1939). 



To summarize: the Austral fauna of Oligochaetes extending from Chile and 

 Patagonia to South Africa across the Falkland islands and New Georgia, 

 and from South Africa to New Zealand across the Crozet, Kerguelen, 

 Macquarie and Campbell islands is one of the most uniform and typical 

 despite its great geographical splitting. 



The situation in the Mexican and Antillean subregions is much more 

 singular than in the rest of America and also a bit more difficult to unravel 

 because of the disorder that remains in some of the taxonomic categories, 

 whereas, it must be stated, the systematics of the South American and 

 South African Oligochaetes revised in the two large monographs by Michael- 

 sen (1917) and Pickford (1937) are in perfect order. 



The Oligochaetes of these central American subregions (which will be 

 dealt with together because they are essentially alike) belong to one family 

 only, the Acanthodrilidae. The recent infiltrations from the South, which 

 reach up to Costa Rica and the island of Barbados, and the admixtures from 

 the north, which have come as far as Guatemala, are of course not counted. 

 They make up a negligible part of the fauna and, except in a couple of 

 cases, do not involve endemic species. 



The four subfamilies of the Acanthodrilidae are represented in central 

 America as follows: there are about a dozen endemic species of Acantho- 

 drilinae, most of which are usually attributed to the genus Eodrihis, but 

 which, in my opinion, would be better placed in a separate genus. There are 

 twenty-two endemic species of Benhaminae belonging to the genus Dicho- 

 gaster found also in equatorial Africa (map. Fig. 7). The Ocnerodrilinae 

 are represented by the genus Nematogenia, which lives exclusively in central 



