SOME ANNELIDS OF THE THAMES VALLEY. 105 



(fig. 1 />). Penis-sheath loiig, intermediate between L. liopneisteri and 

 L. longus ; nearly straight, slender, with trumpet-shaped extremity. Setse 

 one-sixth the length o£ the penis-sheath. 



From the River Lea, Tottenham. Collected by Mr. C. Todd, September 

 1911, in company with the next. 



14. LOINODRILUS TRISETOSUS, sp. n. 



A small, tender worm, o£ 40 segments or more. Length about 10 mm. 

 Front segments biannulate. Setae three throughout. This is a very unusual 

 arranoement in this genus, seeino; that the riile is for the number to decrease 

 behind the girdle. No ventral setse near the male pores, dorsal setse present 

 on girdle-segments. Lower tooth somewhat larger than the upper. Pharynx 

 reaches to end of segment 3 ; chloragogen cells begin in 5, and from the 

 girdle backwards orange and black cells are intermixed, as in L. auranti- 

 •acus, Fr. Nephridia very large in middle segments. Brain slightly concave 

 behind. Spermathecse pear-shaped^ without distinct duct. No spermato- 

 phores at present seen. No penis-sheath, but a widening of the duct near 

 the male aperture. Nerve ganglia in front segments with extensions as in 

 L. nervosus, Friend. 



River Lea, Tottenham_, September 1911. 



15. LiMNODRiLUs AURANTIACUS, Friend. (^ The Naturalist,' 1911, p. 414.) 

 Length G-8 mm. and upwards; 60 segments ; brilliant orange-coloured 



^ells in segments 8-20 or thereabouts. Setse usually five in segments 2-8, 

 and three behind ; varying in size. Penis-sheath slightly bent, about thirteen 

 times longer than broad. Brain roundish with slight concavity behind. 

 Pharynx reaches to posterior end of segment 4. Spermathecse (fig. 1 c) with 

 narrow neck nearly midway between ampulla and duct. Nephridia of tail 

 with very tiny anteseptal. 



Kew Gardens, August 28, 1911. Since found in many other localities 

 around London and in the country. 



The genus llyodrilu-s as defined by Eisen and Stole needs revision in the 

 light of my recent discoveries around London and elsewhere. Hitherto, no 

 one has been able definitely to prove the presence of this genus in England, 

 although Benham long ago suggested that Lankester probably had some 

 species of llyodrilus under examination when he referred to the membrane 

 found stretched across the teeth of some of the setse. This suspicion is 

 abundantly confirmed by my discovery of species of llyodrilus in the Thames, 

 at points not far removed from, if not identical with, those from which 

 Lankester's specimens were drawn. In my study of the British Tubificidse 

 fJourn. R. Micr. Soc, 19th June, 1912, p. 2G8] I have named five species 



10* 



