100 EEV. HILDERIC FRIEND ON 



but in some cases the forks can be seen only with fairly high powers of the 

 microscope. A pair of spermathecae is fomid in segment 9, and the girdle 

 usually extends over 9, 10, and 11. 



2. Stylodrilus vejdovskyi, Benham. (Quart. Journ. Micr. Sc. vol. xxxiii. 

 1891, p. 209.) 



Twenty-five mm., more or less, in length, with penes a little more than 

 half the diameter of the body. First discovered in the River Cherwell, it has 

 since been found by me in many parts of England, but more frequently in 

 the North and Midlands than in the South. It is interesting to see the 

 locality " Goring-on-Thames " in ' Das Tierreich,-* x. p. 63. For details we 

 must refer to the original paper by Benham as above. 



Family Tubificid.e. 



This large and interesting, but perplexing family has been the subject of 

 very special and painstaking investigation during the past year : and though 

 I have not yet by any means worked out all the problems connected tliere- 

 Avith, I have at least reduced some of the chaos to order. I had the honour, 

 on December 20th, 1911, of presenting to the lioyal Microscopical Society 

 some of the results of this enquiry, and may be permitted to refer those who 

 are interested in our fresh-water Annelids to that Memoir for such details as 

 may not be given herewith (11). An old record informs as that specimens 

 of Saenuris tuhifex, or some other " Small red Water-worms (are) found 

 plentifully in the mud of the river Thames " (Johnston, ' Catalogue of 

 British Worms,'' p. 61). Such worms abound everywhere in the Thames, 

 and it is impossible as yet to say to how many species or genera they belong. 

 Perhaps the first reliable record is the following : — 



1. Psammoryctes barbatus [Gruhe) Vejd. ( = Tiih/fe,i- lonhellife)', Lan- 

 kester, Quart. Journ. Micr. Sc. xi. 1871, p. 181 ; Ann. & Mag. N. Hist. 

 ser. ly. vii. 1871, p. 92.) 



Found at Bitrking, then, as now, in brackish water. See Benham (2) p. 208, 

 where will be found a useful note, especially in relation to the setae. 



As I do not follow Michaelsen in placing Heteroclicnla and other genera 

 under Psammoryctes^ this is the only species of the genus to be recorded for 

 the Thames Valley at present. The species, however, is not limited to 

 brackish water, as Benham found it in our district among the roots of reeds 

 in the Cherwell, and I have taken it at Stratford-on-Avon and elsewhere. 



2. Heteroch^ta costata, Clap. 



The anatomy and histology of this species (Benham (2), p. 188 seq.) form 

 what one may call the j&rst classical study of British Tubiticidae. Specimens 



