NEW ENGLISH GENUS OF AQUATIC OLIGOCH^TA. 157 



I. Sparganophilus tamesis, uov. gen., nov. sp., 



is a delicate, pinkish worm, rather narrow for its length of three 

 to four inches. The body-wall is, posteriorly to the clitellura, 

 transparent, and, being provided with a dense network of blood 

 vessels, has a pink colour; but this is complicated by the 

 green colour of the gut, which also shows through. The 

 surface of the body exhibits a lovely violet to peacock-blue 

 iridescence. At the anterior end of the body the pink tint 

 deepens. This is due to the large hearts which exist in the 

 segments here,, while the sperm-sacs give rise to a light 

 cream-coloured band immediately in front of the clitellum, 

 which is itself a bright orange. The worm is very strong and 

 active; it feels wiry and firm, almost like a nematode; it 

 wriggles violently and coils itself when handled. 



The clitellum is quite distinct in the living animal owing 

 to its colour,^ and occupies Somites xvi to xxiv, with part of 

 XV and part of xxv; but in spirit specimens it is difficult to 

 determine its limits, though its area is marked by the sup- 

 pression of intersegmental grooves. Its anterior and poste- 

 rior boundaries are, even when living, very ill-defined, but 

 near its ventral boundary a translucent band — the tubercula 

 pubertatis — is easily recognisable, extending across Somites 

 XVII to XXII, dorsal of the ventral chsetse. In the preserved 

 specimens a deep groove traverses the dorsal surface of the 

 worm, but in the living state the body is cylindrical, the 

 squareness characteristic of Criodrilus not being observ- 

 able. 



The prostomium is small, slightly conical, and not marked 

 off from the peristomium by any groove ; this is the condition 

 Usual amongst the smaller aquatic Oligochseta, whereas in the 

 terrestrial forms a groove forms the hinder boundary of the 

 prostomium; this is but feebly marked in the aquatic Lumbricid 

 Criodrilus. There is no prostomial pore, but in longitudinal 



1 The accompanyiug figures, 1, 2, 3, are lithographed from coloured 

 sketclies, and some of the points which showed well in them are now in- 

 distinct. 



