438 WILHELM MIOHAELSEN. 



it is probable that the specimen was not full-g-ro\vn, although 

 it was sexually mature. 



Head indistinctly prolobous, if not zygolobous. 

 Segments 1-3 simple, 4-10 divided into two ringlets Avhich 

 are about equal in length in segments 4-6 or 7, while the 

 hind one is shorter than the front one in segments 7 or 8-10. 

 Segment 11 and the following are simple or slightly bi- 

 annulated by a rather indistinct furrow in the middle zone. 



The seta3 begin ventrally on the sixth segment, laterally 

 even further back. The ordinary sette are extraordinarily 

 delicate, difficult to detect, and very strictly paired. Median 

 ventral distance distinctly larger than the middle lateral, aa 

 = 1"5-1'8 he. Dorsal median distance equals about two- 

 thirds of the whole circumference of the body, del = circa 

 ^ ti. The position of the lateral pairs of seta? is somewhat 

 irregular, and often distinctly diiferent in two neighbouring 

 segments. 



Clitellum saddle-shaped ; in Beddard's specimen it extends 

 from the fourteenth (?) or fifteenth segment to the hinder 

 border of the twenty-eighth segment, but at the fourteenth 

 segment it is only vaguely developed. In the specimens from 

 Mfongosi the clitellum was not distinctly bordered either in 

 front or behind. 



Copulatory organs : a pair of rather thick and rounded 

 copulatory walls extend from the beginning, middle or end 

 of the sixteenth segment to the end of the twenty-second 

 segment. These walls are on the lines of the lateral setae. 

 They do not extend horizontally, and consequently they do 

 not increase the breadth of the body as in some othei- 

 species of this group, but they extend down vertically. 

 Besides these copulatory walls there is a variable number of 

 copulatory papillte, which bear the sexual seta3, and generally 

 occur in the lines of the ventral pairs of setas. There are two 

 groups of such papilla?. The front group consists of one, 

 two or three pairs on segments 11-13, or on some of them. 

 The most constant is the pair on the twelfth segment ; the 

 pair is absent in only one out of ten specimens. This excep- 



