THE OLIGOOH.ETA OF NATAL AND ZULULAND. 409 



Colour light grey, irregularly mottled by tlie contents of the 

 alimentary canal shining through the body-wall. 



The seta3 are straight for nearly the whole length, but are 

 bent slightly at the proximal end. They occur regularly in 

 pairs throughout the body. 



Dorsal pores are distinct ; they begin on the seventh segment 

 and are placed in the middle of the segments. 



Clitellum ring-shaped, but ventrally it is flatter. It extends 

 from the beginning of the twelfth segment to the end of the 

 middle third of the thirteenth segment. The pellucid gland- 

 cells of the clitellum are arranged in more or less regular 

 transverse rows or zones. 



Internal Anatomy. — Septa between segments 6 and 7, 7 

 and 8, 8 and 9 are somewhat thickened. 



Alimentary Canal. — There are three pairs of main septal 

 glands situated in the foui-th, fifth, and sixth segments, two 

 pairs of smaller intermediary ones in the fifth and the sixth 

 segments and a less distinct pair in the fourth segment. The 

 main septal glands are nearly globular, those of each pair are 

 connected together by a narrow median transverse bridge. 



The peptonephridia are provided with an irregular main 

 portion, which is widest at the ends and somewhat narrow 

 in the middle. In the widened fore-part the lumen shows an 

 irregular undulation, and in the widened hind-part the walls 

 show bladder-like projections, some two of which are pro- 

 longed into narrow diverticula or branches. 



The oesophagus ends and the intestine begins in the middle 

 of the twelfth segment. The front part of the intestine from 

 the middle of the twelfth segment to the end of the fifteenth 

 is provided with a system of " chyle-channels." 



Nervous System. — The brain is only a little longer than 

 broad, rather thick and somewhat convex behind ; it projects 

 in front in a short convex bow. Commissural bands arise 

 laterally from the underside somewhat behind the frontal 

 curve. 



Excretory System. — The nephridia were examined in 

 the segments of the fore-body only as far as the sixteenth 



R Y 



