CLASSIFICATION 155 



I do not attempt the islands of the Pacific, concerning which there is not enough 

 information. 



I have already referred to the resemblances between the Oriental and Australian 

 regions. The latter is, as has been said, sharply marked off from the Antarctic ; nor 

 is there a close resemblance between the Oriental and Ethiopian. The latter is, of 

 course, especially characterized by the Eudrilidae, which, with the exception of the 

 cosmopolitan Eudrilus, are restricted to that region. Some naturalists see a close 

 affinity between the Neotropical and Ethiopian regions. 



The distribution of earthworms offers a certain amount of support to this con- 

 tention. It will be observed that in both continents the family Geoscolicidae enters 

 largely into the composition of the fauna, more, though, it is true, in the case of 

 America than of Africa. It is also, as I point out later, possible to differentiate the 

 old world from the new world Geoscolicids. It seems possible that these resemblances, 

 as also the prevalence of Acanthodrilids in both continents, is due to the former 

 extension northwards of the Antarctic continent. 



PART II. SYSTEMATIC. 

 THE CLASSIFICATION OF THE OLIGOCHAETA. 



Before advancing the scheme of classification of the group which will be adopted 

 in the present work, it is necessary to give a slight sketch of the principal previous 

 systems. 



Historical Survey. LINNAEUS referred such members of the modern order Oligochaeta as he was 

 acquainted with to two different orders of his class Vermes. Nereis lacustris (=Stylaria lacustris) 

 was placed among 'Vermes Mollusca,' Lumbricus among 'Vermes intestina.' 



In the thirteenth edition of the ' Systema Naturae,' GMELIN retained this classification and 

 added to 'Vermes Mollusca' the different species of Nais (described by 0. F. MULLER) ; to 'Vermes 

 intestina' were assigned species of the modern genera Tubifex, Lumbriculus, and Eiicluilrnii/n. 



CUVIER included all the Oligochaeta, together with the Leeches, in one order, Abranchia, of the 

 Anntilata . ; a subdivision of the Abranchia, 'Abranches setigeres apodes' included the two families 

 Lumbricina and Naides. 



The first classification of the Oligochaeta which is of real value, being based upon an anatomical 

 investigation, is that of Jules D'UDEKEM ; this classification he adhered to throughout. At first 

 Milne EDWARDS'S name for the group 'Annelides setigeres abranches" was retained; later 

 SAVIGNY'S term 'Lumbricina' was made use of. The group is divided into two, Monoica and 

 Dioica. The Dioica include the Capitellidae ; the Monoica correspond to the Oligochaeta as now 

 understood (i.e. with the exclusion of the Capitellidae) and are divided into 'Agemmes' and 

 ' Gemmipares.' The 'Agemmes' contain three families (i) Lumbricidae, (2) Tubificidae, (3) Enchy- 

 traeidae ; the 'Gemmipares' only one family Naideae. The distribution of genera in these families 



X 2. 



