178 Proceedings of the Royal Iiish Academy, 



EXPLANATION OF PLATES. 



Plate YIL 



FIG. 



1 . Ophidonais Beckei Floer : 



A. Brain. 



B. Setae. 



a. dorsal seta ; 



b. anterior ventral seta ; 



c. posterior „ „ 



2. iVa^s obtusa (Gerv.) : 



a. ventral seta from second segment; 



b. ventral seta from sixth segment ; 



c. dorsal bundle. 



3. Limnodrilus aurostriatus n. sp. : 



A. Dorsal view of anterior region. 



B. Setae : 



a. anterior ventral seta ; 



b. posterior ventral seta. 

 c. Brain. 



D. Nephridium. 



E. Spermatheca, containing three spermatophores. 



F. Spermatophore. 



G. Penis-sheath : 



a. from side ; 



b. another view of distal end. 



4. Bryodrilus Eldersi Ude. 



Nephridium. 



