SOME ANNELIDS OF THE THAMES VALLEY. 99 



the large number of clear oil globules, whicb after 15 hours in glycerine 

 remained unaffected. Hence the specific name. The first six segments 

 remained intact when all the rest of the worm broke up at the septa into 

 five and thirty pieces. Septa are wanting in this cephalized portion. 



One specimen collected at Kew in August, and kept with other annelids 

 till December 8th, 1911, when it was examined. It closely resembles 

 D. stuldmanni, Stieren, reported from the Victoria Nyanza ; but the African 

 Avorm is only 2 mm. in length and has but 18 segments (Michaelsen, 

 * Das Tierreich,' x. p. 29). 



7. Stylaria LACDSTRis (Liiiii.) JoJinst. is one of our commonest worms. 



8. Pristina equiseta, Bourne. Botanical Gardens, Regent's Park, 

 London. 



Family L u m B R i c u l i D ^. 



Aquatic worms of much larger size than the ^olosomatidse and Naididse. 

 The type {Lumhriculu.< variegatus, 0. F. Miill.) often attains a length of 80 mm. 

 and may have 200 or more segments. The sigmoid seta3 are in pairs, and 

 the free extremity is sometimes forked. With the exception of Stylodrilus 

 (and BiclicBta ?) there are, in this family, blind contractile appendages to the 

 blood-vessels. These are well seen in Lumhriculus variegatus, and give to 

 the animal a very beautiful appearance. There are no penial setae. Only 

 two of the genera are at present known in the Thames Valley. 



1. LuMBRicuLUS VARIEGATUS, 0. F. MulL, Verm, terr, 1774. 



Body usually dark green in front. Posteriorly there are 6-S csecal 

 appendages to the dorsal vessel in each segment. Very rarely found in the 

 adult condition. The worm often divides into two or more portions when 

 handled or under examination. One of the commonest species of freshwater 

 annelids in England, it occurs in almost every pond, ditch, and stream in the 

 district among water-weeds. Yet I sought it in vain at Sutton Broad in 

 August. 



{Rhynchelmis. Beddard says, ' Monograph,' pp. 215-16 : — " I have seen a 

 specimen from some part of England, but cannot give any details. There is 

 every probability that it is a native of the country. I believe this specimen 

 to be in the Oxford Museum." So far as I can recall, Benham, who worked 

 at Oxford, makes no allusion thereto, nor have I been able on the occasion of 

 my visits to obtain specimens or information.) 



The genus Stylodrilus consists of worms which are marked by the possession 

 of a pair of penes on the tenth segment which are not retractile but remain 

 as external appendages, perforated by the sperm-ducts. The setae are bifid, 



