DESCRIPTIONS OF GENERA AND SPECIES 541 



or pear-shaped saccules which ultimately fuse to form a single racemose sperm-sac 

 on each side of gut in segments xi, xii. The spermiducal gland has a remarkably 

 fine lumen. There is apparently a tendency for the glandular cells of its walls to 

 be gathered into separate masses (see p. 118). 



(16) Acanthodrilus falclandicus, BEDDAKD. 



A. georgianus, BEDDAKD, Q. J. M. S, vol. xxx, 1890, p. 421. 

 A. falclandicus, BEDDAKD, P. Z. S., 1893, p. 678. 



Definition. Length about 75 mm. Setae in eight rows, distance separating lateral setae 

 greater than that separating ventral. Prostomium extending on to buccal segment for 

 about one half the diameter. Clitellum, XIII-XVI, complete. No dorsal pores. Gizzard 

 rudimentary in V ; intestine begins in XVI and has a rudimentary typhlosole. Last 

 heart in XIII. Sperm-sacs in XI, XII ; median sperm-reservoir in IX-XV. Penial 

 setae of two kinds, some smooth, some ornamented ; the later with a number of serrated 

 tubercles at free end. Hob. Falkland Islands. 



I originally confounded this species with MICHAELSEN'S A. georgianus. MICHAELSEN, 

 however, in a paper published subsequently to the one in which he first described 

 the species, pointed out the main differences, most of which are indicated in the 

 descriptions of the two species given above. In addition to these I may mention 

 that in A . falclandicus the nephridiopores are directly in front of the third setae. 

 In my definition of A. georgianus I have not referred to the existence of smooth as 

 well as ornamented penial setae ; these are, however, figured by MICHAELSEN (15, 

 PL ii, fig. 4 c), but he has expressed the opinion that the smooth setae are so 

 because they are immature. I do not think this myself or I should emphasize this 

 as a further difference between the species. A. georgianus seems to want the 

 median sperm-reservoir of the present species, as well as the septal sacs ('glycogenic 

 organs '). MICHAELSEN has suggested that A. falclandicus is synonymous with KOSA'S 

 A. bovei. There is, I have pointed out (57> p- 679), no doubt that they are near to 

 each other ; but not, I think, identical. As, however, EOSA'S description is, on 

 account of the poorness of his specimens, in some respects defective, it is not easy 

 to be quite certain. In the meantime A. bovei is a much smaller species ; the 

 tubercles on the penial setae are not stated to be denticulate as they are in A. 

 falclandicus; the clitellum of A. bovei has, as is the case with A. georgianus, a 

 median non-glandular area on segments xv, xvi. In A. falclandicus, however, the 

 same space may be occasionally seen, so that this character is not likely to 



