THE OLIGOCH^TA OP NATAL AND ZULULAND. 413 



segment, and are reflected sliglitly towards the middle 

 ventral line. 



Spermathecal pores in two pairs are on the furrows 

 between the seventh and eighth segments, and the eighth 

 and ninth segments in the lines of set^e h. 



Internal Anatomy. — The septa of the gizzard region are 

 extraordinarily tender. Septa between the ninth and tenth 

 segments, tenth and eleventh segments and the eleventh and 

 twelfth segments are very little thickened, and must still be 

 regarded as thin. 



Alimentary Canal. — Gizzard small, hardly broader than 

 the neighbouring part of the (lesophagus ; occurs in the fifth 

 and sixth segments. Esophagus without calciferous glands. 

 Intestine without typhlosole. 



Circulatory System . — Dorsal vessel simple ; the last 

 hearts are in the twelfth segment. 



Reproductive System. — Male organs: one pair of 

 great sperm-duct funnels occur free in the tenth segment, 

 they are not enclosed in seminal vesicles. There are two 

 pairs of great grape-like sperm-sacs depending from the septa 

 between the ninth and the tenth segments and tenth and 

 eleventh segments. They project into segments 9 and 11. 



Prostates are tubular ; the glandular part is very long and 

 richly folded in broad and narrow coils, which extend from 

 the segment of the prostate pores into the segment in front. 

 Duct is relatively short, somewhat bent^ and much thinner 

 than the glandular part. 



Penial setfB are of two kinds ; each prostate is accompanied 

 by one of both kinds. (1) Length 1'2 mm., thickness at 

 pi'oximal end about 35 ju. The seta gradually diminishes 

 towards the tip, close to which the thickness is about 20 fx. 

 The seta of this kind is distinctly bent, and ends in a very 

 sharp point. With the exception of the terminal pointed 

 jDortion, the distal third of the seta is ornamented with a 

 somewhat close annulation. The edge of the annulets consists 

 of densely crowded, irregular triangular teeth closely clinging 

 to the surface, and forming irregular zigzag transverse rows. 



VOL. 2, PART 4. 28 



