Mr F. E. Beddard on a New Nematoid Worm. 233 



short distance, is bent upon itself, and continues its course as 

 a straight tube to the end of the body, where it opens on to 

 the exterior ; the posterior half of the tube is not concerned 

 in the production of the spermatozoa, and serves as a vas 

 deferens. At the opening of the vas deferens three chitinous 

 spicules are found, of which one is rather smaller, and cor- 

 responds to what is called in other Nematoids the " accessory 

 piece." 



Having described the anatomical characters of this Nema- 

 toid, its systematic position remains to be decided. The 

 presence of the two caudal suckers and the single mouth 

 papilla are, perhaps, the most salient characters, and of these 

 the caudal suckers distinguish the genus Dicelis* This 

 genus was founded by Dujardin, in 1845, for the reception of 

 a parasitic worm occurring in the testes (vesiculse seminales) 

 of the common earthworm. There is only one species {D. 

 filar ia) which is characterised by two suckers on either side 

 of the tail behind the anus, arranged symmetrically ; the tail 

 is very short; the mouth unprovided with papillae; the 

 oesophagus muscular ; the integument transversely striate ; 

 the male provided with two spicules, and an accessory piece. 

 It is clear, therefore, that my Nematoid forms a well-marked 

 new species, and I propose to call it Dicelis Fleurochcetce, the 

 specific name recording the genus of which it is a parasite. 



D. Fleicrochcetce, although a parasitic form, shows a good 

 many resemblances to the free -living Nematoids, which 

 group, according to Dr Bastian,-|- form not only a physio- 

 logical but also a morphological assemblage, agreeing among 

 themselves, and differing from the parasitic genera in a num- 

 ber of anatomical characters. Those cases where Nematoids 

 are found seemingly as parasites, though with structural 

 affinities to the free-living forms, may sometimes be explained 

 by the hypothesis that they are accidentally present in the body 

 of their host. Dorylaimus stagnalis, found by Dujardin \ in the 

 intestine of the carp, had in all probability been swallowed 

 along with the food of the animal ; and Dicelis filaria may 

 easily, Dr Bastian suggests, have found its way when young 



* Dujardin, Hist. Nat. des Helm. (Paris, 1845), p. 108, and PI. iii., Fig. h. 

 t Trans. Linn. Soc, 1865. X Dujardin, loc. cit., p. 231. 



