Southern — Monograph of the British and Irish Oligochceta. 133 



thick, pointed seta, having a node near the distal end (fig. 1, b, a). The 

 ventral bundles contain 3-5 setse. In the anterior bundles the node is in 

 the proximal half (fig. 1, B, b). Behind the fifth segment, it is in the centre; 

 and in the posterior setse, it is in the distal half (fig. 1, b, c). This appears 

 to be the opposite arrangement to that found in 0. serpentina. Length 

 10-15 mm. 



January (im.). 



Hahitat — Ireland. Pond in Phoenix Park, Dublin. 



Distribution — Germany. 



Nais obtusa (Gerv.). 

 Plate VII., fig. 2. 



1891. N. harljata. Bourne in Q. Journ. Micr. Sci., vol. xxxii., p. 344. 



1892. N. larlata, Benham in Q. Journ. Micr. Sci., vol. xxxiii., p. 214. 



I have on several occasions found ISTaids which must be referred to this 

 species. It is evidently very variable, as the figures of the ventral setee 

 given by various writers differ greatly. The drawings given (PI. vii., fig. 2, 

 a, b) were carefully drawn to scale, and differ from those given by Vejdovsky 

 (28. PL II., fig. 24). They agree fairly well with the Swiss specimens 

 figured by Piguet (24. PI. 12, fig. 8, b, c). The dorsal bundles (PL vii., 

 fig. 2, c) are composed of two kinds of capillary set^e, the shorter ones being 

 curved near the middle, and about -^ the length of the long ones. Each 

 bundle contains 1-2 long, and 2-4 short setee. 



January (im.), March (im.), August (im.). 



Hahitat — Ireland. E. Dargle, Powerscourt, Co, Wicklow ; Pond in 

 Phoenix Park, Dublin ; Pt. Annalee, Ballyhaise, Co. Cavan. 



Distribution — England. Europe. Asia (Lake Baikal). 



Nais elinguis Milll. 



1891. N.e., Benham in Q. Journ. Micr. Sci., vol. xxxiii., p. 212. 



1907. N.e., Southern in Irish Nat.^ vol. xvi., p. 69. 



The Irish specimens of this species differ in some small points from the 

 figures given by Vejdovsky (28. Taf. 2-3). The ventral sette of segments 

 2-5 are slightly longer, straighter, and much slenderer than those of the 

 following segments. The prostomium is conical, or rounded, only as long as 

 the base is broad. 



January (im.), February (im.), April (im.). May (im.), October (im.). 



