Southern — Monograph of the British and Irish Oligochceta. 125 



to Ireland. If, as Michaelsen avers, the whole earthworm fauna of Ireland 

 has arrived since the close of the Ice Age, there must have been a land- 

 connection. 



It seems, therefore, that we are compelled to fall back on the third 

 hypothesis, that in some way the fauna survived the Ice Age, either in 

 Ireland or in some neighbouring land free from ice, and in connection with 

 Ireland. It has been suggested that there was such an extension to the 

 south-west. But even this latter assumption is unnecessary. In discussing 

 the presence of a large endemic earthworm fauna in the Alps, which must 

 have been strongly glaciated, Michaelsen (22. p. 180) suggests that the 

 original fauna may have survived in small oasis-like areas between the 

 glaciers. In the same way, in Co. Kerry, which was near the extreme south 

 of the glaciated area, there may have been small areas free from ice, in which 

 a remnant of the original earthworm fauna survived. The age of the Irish 

 earthworm fauna is attested by the absence of the sub-genus Eophila, and the 

 presence of a small group of species having a discontinuous distribution of 

 the Lusitanian type, admittedly the oldest in our fauna. 



As regards the aquatic families of the Oligochseta, and the Enchytrseidee, 

 our knowledge of their distribution is at present quite inadequate to allow any 

 general conclusions to be drawn from it, as may be seen from the large 

 number of new records in this paper. 



I have drawn up a list of species known to occur in the British Isles, 

 showing our present knowledge of their distribution in the various regions, in 

 a convenient form for reference. Those species which are here recorded for 

 the first time from the different countries are marked with an asterisk. 



List of the Oligoch^ta occueeing in the Beitish Isles. 



Species. 



England. 



Scotland. 



Wales. 



Isle 

 of Man. 



Ireland. 



Aeolosmatid^ij. 

 iEolosma quaternarium, EhrL., 



A. Beddardi, Mchlsn., 



A. Heniprichi, Ehrbg., 



A. Headleyi, Beddard, 



A. variegatum, Vejd., 



A. tenebrarum, Yejd., 



X 

 X 

 X 

 X 



X 



X 

 X 





— 



1 1 *X 1 X 1 



