426 WILHELM MICHAELSEN. 



nearly straight. 'J^he distal ei)d is thickened and broadened 

 to a diameter of about 80 fx just beneath the tip. One side of 

 this broadened portion is strongly convex, the other side is 

 flat or slightly concave or provided with a longitudinal cleft. 

 The seta ends in a simple and rather clums}^ tip, or in two 

 tips with a slightly concave edge between them. In the type- 

 specimen all the sexual setae had only one point. In one of 

 the specimens from Pieterniaritzburg about half of the sexual 

 setae were provided with two tips while the other half had 

 only one. There is a veiy characteristic external ornamenta- 

 tion consisting of somewhat irregulai', rather densely crowded 

 annulations, the distal borders of which are rather prominent 

 and almost scale-like. From the distal border of these 

 annulations a closely set row of very slender teeth, clinging 

 to the surface of the seta, extend distalwards, and nearly 

 reach the distal border of the next annulus. This ornamenta- 

 tion was not very clearly seen, as the sexual setse were 

 enclosed in a fine cuticular sheath difficult to remove. In the 

 type-specimen the sexual setfe are not fully developed, and 

 hence they differ in shape and structure. 



There are no special glands connected with the sexual setfe 

 projecting into the body-cavity as are found in other species 

 of this genus. 



The sexual setas ofM.natalensis are provided with a very 

 strong mantle of longitudinal muscles, which at one end are 

 fixed to the proximal portion of the setal sac, and at the other 

 to the body-wall in the immediate neighbourhood of the setal 

 pore. 



Microchastus papillatus J5e7i/w77i f . typicus. PL XXXII, 



fig. 10. 



Microchseta papillata Benham, "Descriptionsof Three New Species 



of Earthworms," Proc. Zool. Soc. Lond., 1892, p. 141, pi. vii, figs. 5, 



7; pi. viii, figs. 9, 10, 11. 13. 

 Microchsetus papillatus Berth.; Micliaelsen, " Oligocliseta," Tier- 



reich, x, p. 450. 1900. 

 Microchsetus papillatus Benh.; Micliaelsen, " Oligocheeteu von 



Natal und dem Zululand," Arkiv. Zool., iv, n. 4, p. 5. 1907. 



