iQoS.] W. M1CHAE1.SEN : Oligochœta of the Indian Empire and Ceylon. 129 



prevalent in North-Kast Africa). But we have no information about the exact path 

 along which these forms may have migrated. The very questionable relation of the 

 Indian region to Madagascar (of Odochœtus to Howascolex) was mentioned above ; it 

 would be premature to state any hypothesis as regards it. 



RECENT REGIONS AND SUB-REGIONS OF TERRESTRIAL 



OUGOCH.ETES. 



In my memoir on the geographical distribution of the Oligochaetes ' I defined the 

 different recent regions and sub-regions characterised by certain groups of terrestrial 

 Oligochaetes endemic therein. As for the part of the world here in question, I assigned 

 it to three different regions (see the geographical sketch, I.e., p. 154). In this statement 

 Burma and the adjacent parts of East Bengal, as well as the districts north-north-east 

 of it, formed the north-western part of the " Indo-Malayische Terricolen-Gebiet ," the 

 empire of India with the exception of the said extreme eastern part of Bengal formed 

 the " Vorderindische Terricolen-Gebiet ," divided into two sub-regions, a broader northern 

 one and a small southern one, and finally Ceylon, the small " Ceylonische Terricolen- 

 Gebiet." The present study of the Indian Oligochsete fauna requires an amendment 

 of these limitations. The error in the latter is principally based on the incompleteness 

 of BOURNE'S faunistic studies. BOURNE described a great number of Drawida 

 species from South India, but only very few species of other genera. Just those genera 

 which South India shares with Ceylon were neglected by BOURNE. Consequently the 

 known Oligochaete-fauna of South India assumed quite a distorted appearance. It 

 must be said that this was no fault of BOURNE'S, for he expressly stated that 

 he had studied and published only part of all his material, and that there were many 

 representatives of other genera in his collection. The fault is mine in that I overlooked 

 this remark of BOURNE'S. 



The principal amendment then to be stated here is the separation of the South 

 Indian sub-region from the great Indian region, and the joining of the former to the 

 Ceylon region. The terrestrial endemic Oligochaetes of South India and Ceylon are 

 nearly identical as regards genera. It is true that South India lodges some endemic 

 species of Octochœtus and Lampito , hoth. these genera being missed in Ceylon. But 

 Octochœtiis occurs also in the north-eastern part of the Indian Peninsula, and forms not 

 merely a feature of the South Indian fauna. Lampito also shows near relations to the 

 northern region. The occurrence of these forms may only require a subdivision of 

 the South Indian-Ceylon region into a South Indian and a Ceylon sub- 

 region {Süd- Indische und Ceylonische Subregionen des Süd-Indisch- 

 Cey Ionischen Terricolen- Gebiets). The limit of this southern region may be 

 a west-eastern line somewhat north of the latitude of Madras. 



The " Vorderindische Terricolen-Gebiet," then, must be restricted to that part 

 of the Indian Empire north of that latitude and its name must be changed into 

 " Northern Indian region " {Nord- Indisches Terricolen-Gebiet). The eastern 



W. MICHAElySEN, Die geographische Verbreitung der Oligochaeten, Berlin, 1903. 



