DESCRIPTIONS OF GENERA AND SPECIES 481 



I follow MiCHAELSEN in allowing only a single species of this genus, which must 

 be named — 



Pletcherodrilus unicus, Fletcher. 



Cryptodrilus(?) unieus, Fletchee, Proc. Linn. Soc. N. S. W., iii. (z), 1889, p. 1540. 

 C. purpureus, Michaelsen, JB. Hamb. wiss. Anst., vi, 1889, p. 3. ' 



Cryptodrilus (?) purpureus, Fletcher, Proc. Linn. Soc. N. S. W., iv. (3), 1890, 



p. 990. 

 C. (?) fasciatus, Fletcher, p. 988. 

 Pletcherodrilus unieus, Michaelsen, JB. Hamb. wiss. Anst., viii, 1891, p. 29. 



Definition. Length, up to 335 'n^in.; breadth, 10 mm.; number of segments, 159. Dorsal 

 pores commence between IV/V. Gizzard in FI; three pairs of calciferous glands in 

 XIII-XV. Clitellum, XIII-XVIII. Sperm-sacs in segments IX-XII. Last pair of 

 hearts in XIL Hab. — Queensland ; N. S. Wales ; Pelew Islands. 



Although Michaelsen stated that his C. purpureus agreed ' point for point ' with 

 Fletcher's C. unieus, the latter author retained the two species, adding to them 

 a third species, C. fasciatus. After the publication of the paper in which Fletcher 

 distinguished the three species, Michaelsen again emphasized the real identity of 

 the three ;' Fletcher used as points of difference the stouter form of the body in 

 the species 'fasciatus,' and also mentioned that the setae are straight in fasciatus,' 

 while they are sinuous in 'purpureus.' The irregularity of the setae, however, varies 

 very much in individuals, and is, perhaps, therefore, hardly to be used as a specific 

 character. Some worms from Percy Island, described by Fletcher as ' incertae sedis,' 

 appear, according to his latest opinion, to be referable to this species. The examples 

 from the Pelew Islands are much larger than the others. The additional pair of 

 sperm-sacs described by Fletcher, on the posterior face of the septum xii/xiii, are 

 possibly egg-sacs (cf. Perichaeta, see p. 97). 



Genus Tbinbphbxjs, Beddard. 



Syn. Cryptodrilus, Fletcher, Spencer (in part.). 



DEPiBriTioif. Three pairs of nephridia in each segment. Spermiducal glands either 

 lobate or tubular. 



3Q 



