igoS.] W. MiCHAEi<SEN : Oligochcata of the Indian Empire and Ceylon. 115 



UMNIC OLIGOCH^TES. 



The limnic Oligochsetes of our region belong mostly to the most archaic families 

 Molosomatidœ and Naididœ. Not only the genera of these but also most of their 

 species have a very wide distribution, some of the latter being cosmopolitan or nearly 

 so, as iox instdince Chœtogaster limnœi, Nais elingids, Pristina longiseta and P. œqui- 

 seta. Only a few species seem to be more restricted in their distribution, as for in- 

 stance Aulophorus toizkinensis , or are found only in this region, viz., some Chœiogaster 

 species, Branchiodrilus semper i and Pristina hreviseia. (The genus Pleurophleps and 

 its species are far too doubtful to be included in any geographical discussion.) More- 

 over, as the region in question and the adjacent regions are not yet well studied in 

 respect to limnic forms, we dare not regard these species as endemic. Nor can we 

 characterize any regions by these as a rule widely distributed, nearly cosmopolitan 

 genera. 



No better results are given by the study of the Tubificids, which seem to be very 

 scarce in all regions south of the northern temperate zone. They are represented 

 by a species of Bothrioneurum, belonging to a genus which has otherwise been found 

 in Bj.rop2 and Soiith Ansrica. The scarcity of Tubificids corresponds with the 

 apparent absence of Lumhriculidce , a family found only in the northern temperate 

 and cold zones and particularly prevalent in I^ake Baikal, and with the apparent 

 scarcity of Enchytrseids, also prevalent in the more northern zones. If the species 

 spuria iVaisa/ôîV^«, CARTER, be not an Enchytrseid, we know only one Indian species 

 of this family, namely, Henlea lefroyi, BEDD. Further, I do not believe that this 

 species really belongs to the genus Henlea, but rather believe it to be a Marionina or 

 Liimhricillus. It is quite uncertain, moreover, whether it should be regarded as en- 

 demic or as an imported peregrine species. 



The higher families of Oligochœtes are represented only by one species in the limnic 

 fauna of our region, probably a species of Glyphidrilus , with less probability a Callidri- 

 lus, certainly a species of Microchcetinœ. If belonging to Glyphidrilus , this species 

 would be a connecting link between the Burmo-Malayan group of this genus and the 

 somewhat isolated species of tropical East Africa. If belonging to C alii dri lus, it 

 would represent nearer relations only to tropical East Africa. 



LITTORAL OLIGOCHŒTES. 



We know only one Littoral Oligochsete from our region, viz., Pontodrilus insularis 

 (ROSA) from Ceylon. As the genus Pontodrilus is circummundane in the warmer 

 zones, its occurrence does not enable us to characterize any special region. 



TERRESTRIAL OLIGOCHŒTES. 



i 



The terrestrial species represent the bulk of the Oligochsetes, and only they pro- 

 vide us with interesting geographical results. But to get at these results we first 



