Southern — Monograph of the British and Irish Oligochceta. 169 



Habitat — 1vg\q.\\([. Cos. Kerry, Cork, Limerick, Wicklow, Dublin, 

 Kildare, Meath, Cavan, Galway, Down, Antrim, and Donegal. 

 England. Lancashire (Adlington.). 

 Wales. Merionethshire (Barmouth). 

 Isle of Man. Snaefell summit (2000 feet). 

 Distribution — British Isles ; Europe ; Asia Minor ; North America. 



?Helodrilus (Allolobophora ?) relictus n. sp. 



Text figs. 2 and 3. 



This species, of which only a single specimen was obtained from Clare 

 Island, off the west coast of Ireland, is so remarkable in structure that I 

 hesitated for some time whether to describe it as a new species or to regard 

 it as a monstrosity. There is no doubt that the specimen is an abnormal 

 one. This is clearly shown by the spiral arrangement of some of the 

 segments (fig. 2, infra), which are divided and contain two sets of setae on one 

 side, whilst they are single and with only one set of setss on the other. The 

 male reproductive organs also are quite unique amongst the Lumbricidee; and 

 the whole structure differs widely from that of any other British type. It is 

 not justifiable, however, to regard all its specific differences as being due to 

 individual mutation, since it approaches in structure two species, H. {A.) 

 Molleri, and H. {A.) Mobii, the former occurring in Portugal, the latter 

 in Madeira, the Canaries, and Tangiers. Taking into account its relation to 

 these two western species, and its occurrence on an isolated island off the 

 west of Ireland, one is tempted for the present to regard it as a surviving 

 member of a very old species. It is probable that more^ material will shortly 

 be obtained from Clare, Island, and new light may be thrown on this iaolated 

 form. 



External Characters. • - 



Length, 40 mm. ; width, 2 mm. ; number of segments, 126. Dorsally the 

 worm is dark purple, the anterior segments shining with a greenish-purple 

 iridescence. The ventral surface is much paler. The prostomium cuts 

 back to the second segment, as in the genus Lumbricus. So far as could be 

 ascertained the first dorsal pore is between segments 11 and 12. The setae 

 are closely paired ; ab is slightly greater than cd ; aa = iab, be = Sab. The 

 setsB ab are more prominent than cd all along the body. The spiral arrange- 

 ment of the segments makes it difficult to state the exact position of the 

 various papilke, the clitellum, &c. They are shown in fig. 2. The chief 

 aberrations are : — 



1. On the 15th segment there are two pairs of lateral setae on the right 

 side. 



2 [0*1 



