igoS.] W. MiCHAELSEN : OligochcBta of the Indian Empire and Ceylon. 205 



OCTOCILISTUS PHII,I.OTTI, MlCHI^SN. 



(Plate xiv, figs. 65 — 67.) 

 0. ph., MICHAELSEN, in Mt. Mus. Hamburg, xxiv, p. 169. 

 Examined about a dozen mature specimens and some younger ones. 



External Characters, — Dimensions of the mature specimens : I^ength 

 35 — 55 mm., greatest thickness 2 — 2| mm., number of segments ca. 125. 



Colour greyish. 



Head epilobous (about |). Prostomium small. Hinder dorsal appendix of 

 prostomium moderately broad, open behind. 



Setae rather small, paired, but in general not very strictly, the ventral somewhat 

 more strictly than the lateral, especially at the clitellum and at a number of preceding 

 and succeeding segments {ab<cd). The median lateral distances about i|- times 

 the width of the dorsal pairs and about f as large as the median ventral distance (be 

 = 1 cd = ^ aa) . Median dorsal distance somewhat larger than half the circumference 

 of the body {dd = j u). 



' First dorsal pore on the intersegmental furrow 11-12. 



Clitellum ring-shaped, extending over segments 13 — 17 ( = 5). 



Prostate pores on the 17th and 19th segments in the lines of setae a. 



Seminal furrows nearly straight, curving only very slightly towards the median 

 ventral line. 



Male area much depressed, bordered at the side by broad, almost wall-like 

 protuberances which often somewhat overhang at the i8th segment, giving the 

 depressed male area a biscuit-like form. 



Female pores at the 14th segment before the zone of setae somewhat medially 

 in the lines of setae a, on a common biscuit-shaped glandular area. 



Spermathecal pores on the 8th and 9th segments just before the setae a. 



Copulatory organs: The ventral part of segment 18 and sometimes 20 

 may be somewhat glandular. Also the ventral part of the 8th and 9th segments is often 

 glandular. Sometimes the spermathecal pores of one segment are connected with each 

 other by a backward-curved transverse furrow. Sometimes the hinder border of this 

 furrow appears wall-like. 



Internal Anatomy. — Septum 4-5 is very strong ; septa 5-6 and 6-7 are very 

 tender, apparently rudimentary (not reaching the gizzard ?) ; septa 7-8 — 14-15 

 are strengthened, especially lo-ii, 11-12 and 12-13, the others gradually somewhat less ; 

 septum 15-16 is tender, but somewhat thicker than the following ones which are very 

 tender. 



Alimentary tract: A big somewhat oblique gizzard between the thickened 

 septa 4-5 and 7-8. CEsophagus narrow, with folded walls. A pair of big calciferous 

 glands in the 15th segment surrounding the oesophagus dorsally and laterally. These 

 calciferous glands are divided by a great number of longitudinal septa and are each 

 connected with the oesophagus by a very short and narrow stalk. Intestine beginning 



