658 OLIGOCHAETA 



(i) Pontoscolex corethrurus (F. Mdllee). 



Iiumbricus corethrurus, Fbitz Mullbe, Arch. f. Nat., 1857, p. 113. 

 Uroehaeta hystrix, Peeeiee, Nouv. Arch. d. Mus., 1873, p. 14a. 

 XT. sp., Beddaed, Proc. R. Soc. Ed., vol. xiv, 1887, p. 160. 

 IT. corethrura, Beddaed, Q. J. M. S., vol. xxix, 1889, p. 235. 

 IT. dubia, HoEST, Midden Sumatra iv, Zoologie xii, Vermes, p. 7. 

 P. corethrurus, HoEST, Zool. Ergebn. Ost-Ind., Bd. ii, p. 51. 



Definition. Length, 60 mm. ; diameter, 4 mm. ; number of segments, aao. Setae hijid 

 at extremity, slightly ornamented; clitellar setae with a more marked, ornamentation; 

 paired in anterior {ten to twelve)) segments, displaced and irregular later. Clitellum, 

 XIV {XV, XVI)-XXI {XXIII), saddle-shaped. Prostomium absent (?). Dorsal vessel 

 single; hearts in XI, XII. Calciferous glands in VII, VIII, IX. Spermathecae in VI, 

 VII, VIII. Hob. — Java ; Sumatra ; (Queensland ; Burmah ; Brazil ; British Guiana ; 

 Mauritius; W. Indies; Singapore. 



This species is one of the most widely spread, and one of the most abundant of 

 exotic earthworms. It may be that there are varietal or even specific differences 

 between individuals coming from such widely distant localities, as for instance, 

 Australia and Brazil. In the meantime these differences have still to be put on 

 record. The Australian (Queensland) specimens at one time appeared to me to 

 differ. I can now detect no difference except perhaps that they are rather larger. 

 HoEST (17) accepts Rosa's identification of his Uroohaeta dubia with the type- 

 species. 



The setae show some variation as to the segment in which a displacement 

 commences. I found (in two specimens from Australia) that on the first eight 

 segments the setae were distinctly and strictly paired. On the tenth segment (ninth 

 setigerous) the ventral setae became separated ; on the following segment the dorsal 

 setae also. Hokst found (in specimens from Java and Sumatra) that the setae of 

 the ventral pairs begin to diverge in the eleventh segment, those of the dorsal 

 couple in xii ; behind the clitellum the setae begin to alternate, the dorsal ones 

 first. HoEST first put on record the fact that the setae are ornamented at the free 

 extremity, they having been previously described as smooth, except, of course, the 

 modified setae of the clitellum. This ornamentation is but faintly marked (as is 

 also shown by the fact that other observers have not commented upon it) as 

 compared with P. ha/waiensis. In one out of a large number of specimens from 



