Ie32 Proceedings of the Royal Irish Academy. 



Chaetogaster crystallinus Vejd. 



? 1869. Chcetogaster niveus, Lankester in Trans. Linn. Soc. London, 

 vol. xxvi., p. 641. 



? 1893. C. c, Hartog in IrUi Nat.,Yo\. ii., p. 117. 



This species is recorded by Prof. Hartog from Cork (torn, cit.], but as he 

 described it as " a large species, revealing its structure under a pocket-lens," 

 the record is somewhat dubious. 



January (im.). May (im.}. 



Habitat — Ireland. In weeds from R. Dargle, Powerscourt, Co. Wicklow ; 

 Pond in Phoenix Park, Dublin. 



Distribution —Middle Europe. 



Ophidonais serpentina (Mull.). 



1886. Slavina serijentina, Bousfield in Journ. Linn. Soc, vol. xix., p. 268. 

 The individuals of this species were enveloped in a very delicate tube, 

 coated with fine particles of mud. 

 March (im.). 



Habitat — Ireland. E. Annalee, Ballyhaise, Co. Cavan. 

 l)istrihutio7i — England ; Europe. 



Ophidonais Reckei Floericke. 

 Plate VII. , fig. 1, A-B. 



1892. O.R, Floericke in Zool. Anz., vol. xv., p. -470. 



The brief description of this species given by Floericke refers mainly to 

 the character of the dorsal setse, which differ from those of 0. serpentina in 

 being pointed, and not bifid, at the distal end. In other respects the two 

 species are said to be similar. This form does not appear to have been 

 recorded since. I found several specimens of a worm in a pond in the 

 Phcenix Park, Dublin, which must be referred to this species. The worms 

 are enveloped in a very fine tube, probably of mucus secreted by the 

 whole body. To this tube, fine particles of mud are attached. The whole 

 tube is quite flexible, and allows the worm to wriggle about without 

 apparently incommoding it. When the tube is removed, the body of the 

 worm is seen to be quite transparent. The eyes consist of large irregular 

 masses of dark pigment, just in front of the corners of the mouth. The 

 brain (PI. vii., fig. 1, a) is concave in front, and deeply cut behind. The 

 dorsal bundles commence in the sixth segment, and contain a single short, 



