540 OLIGOCHAETA 



Definition. Length, 38-47 mm.; number of segments, 92. Prostomium round, imbedded in, 

 but not continued by grooves on to buccal segment. Setae in eight rows, those of ventral 

 pair approach each other more closely in segments X7I-XIX. Clitellum, XIII-XVI, 

 complete. Spermathecae each with two diverticula. Sperm-sacs three pairs in X-XII, 

 the last pair racemose, the others not so. Penial setae with numerous small spines 

 the apices directed forwards on free extremity. Hab. Kerguelen, Marion Island. 



That Lumbricus kerguelarum of GRUBE was in all probability an Acanthodrilus 

 was first pointed out by myself (41, p. 301, footnote). VAILLANT, nevertheless, 

 ranged it (6, p. 167) in the genus Lumbricus, though certainly putting the species 

 among 'Lumbrici dubii.' GRUBE'S description is given in full, and it is curious that 

 VAILLANT did not suspect that the 'papillae' of the seventeenth and nineteenth 

 segments, were, as I suggested, the male pores ; VAILLANT did, however, go so far 

 as to suggest that the worm might belong to the intraclitellian group of PERRIEK. 

 The justice of my own suggestion was confirmed later by MICHAELSEN who ex- 

 amined the types. MICHAELBEN considered that the species was not identical with 

 LANKESTER'S A. kergudenensis ; this opinion was chiefly based upon differences in 

 the shape of the penial setae, which seem to me to be too slight for recognition. 



I have examined a single specimen evidently referable to the same species, which 

 was collected during the voyage of H.M.S. ' Challenger ' on Marion Island. I have, 

 therefore, been able to fill up a few lacunae in the previous descriptions, which are 

 incorporated in the above definition. This species comes, perhaps, nearest to A. 

 capensis, but is to be distinguished from it by the arrangement of the setae. 



(15) Acanthodrilus georgianus, MICHAELSEN. 

 A. Georgianus, MICHAELSEN, JB. Hamb. wiss. Anst., v, 1888, p. 68. 



Definition. Length, 60 mm. ; diameter, 5*5 mm. ; number of segments, 87. Prostomium 

 prolonged over two-thirds of luccal segment. Clitellum, XIII-XVI, incomplete on last 

 two segments. Setae four pairs, but the individual setae are at some distance from 

 each other ; posteriorly the setae are separated by equal intervals ; anteriorly there is a 

 tendency to a paired arrangement. No dorsal pores. Nephridiopores in front of 

 interval between setae 2 and 3, but nearer to latter. No gizzard ; typhlosole completely 

 absent. Sperm-sacs in, XI, XII. Spermathecae two pairs in VIII, IX ; each with two 

 diverticula. Penial setae with a few blunt tubercles on free extremi/y. Ilab.- South 

 Georgia. 



The sperm-sacs are said by MICHAELSEN to arise as a number of separate spherical 



