210 



Memoirs of the Indian Museum. 



[Vol. I, 



Fig. 22. 

 Octochœtus pattoni. 



mostly paired, on each side between the lines of setae a and c, sometimes somewhat 

 nearer together or even united in the ventral median line (but 

 without getting unpaired), in variable number and situation. The 

 most constant, in thirteen out of twenty-three mature specimens, 

 on the intersegmental furrow 11-12, in eight of the twenty-three 

 specimens a pair on the intersegmental furrow 14-15, in nine speci- 

 mens a pair on the intersegmental furrow 21-22 or 22-23. Only in 

 two specimens all of them were present, in three mature specimens 

 only they were totally absent. In four specimens more or less distinct 

 glandular cushions of a somewhat varying appearance were found 

 on segments 7 and 8 or 8 and 9. These cushions were unpaired, 

 transversely-median, or, if paired, connected in the middle line. 



Internal Anatomy. — Septum 5-6 strong, 6-7 — 8-9 very 

 thin, apparently partly rudimentary, 9-10 thin, dorsally dislocated 

 backwards, not reaching the body-wall, united with the strong 

 septum lo-ii, forming a rather small ventral chamber with the 

 latter. Septum 11-12 strong, dorsally dislocated forward and united with the 

 preceding septum lo-ii forming with it a small ventral chamber. Septum 12-13 and 

 13-14 strong, 14-15 somewhat strengthened, about half as thick as the preceding 

 ones ; those that follow are thin. 



Alimentary tract: A big somewhat oblique gizzard between the two first 

 strong septa 5-6 and lo-ii, apparently enclosed by the thin septum 6-7 (in 

 segment 6 ?). CEsophagus thin, with much folded walls. A pair of very large, 

 densely striated calcif erous glands opening by short and thin stalks into the œsophagus 

 near each other and near the dorsal median line, at about the border-line between 

 segments 15 and 16 (just behind this line in the i6th segment ?). The calciferous 

 glands are not arranged symmetrically, the one extending into the 15th segment, the 

 other into the i6th. Intestine beginning in the 19th segment, with a big typhlosole, 

 consisting of two longitudinal edges with a common basal part. 



Nephridial system micronephric. ' 



Anterior male organs : Two pairs of testes and two pairs of sperm-duct-fun- 

 nels, imbedded in developing sperm-masses, lie in the two rather small ventral 

 chambers which represent the reduced segments 10 and 11. Two pairs of grape-like 

 sperm-sacs depend forward and backward from the dorsally united septa 9-10 — 11-12. 

 These sperm-sacs, — one pair evidently depending from the front of septum 9-10, the 

 other pair evidently depending from the back of septum 11-12, — therefore lie 

 in segments 9 and 12, the more archaic arrangement often seen in the sub-family 

 OdochœtincB. This curious arrangement shows the sperm-ducts, which are very long 

 and form in segments 11, 12 and 13 big, nearly compact convolutions, lying free in the 

 cœlomic cavity. The convolutions of the 13th segment are not quite as big as those of 

 the preceding segment and pass backwards without a sudden break over into the 

 dense undulations of the hinder part of the sperm-ducts. The two sperm-ducts of 

 one side do not unite until they pierce through the body-wall just before opening 

 by the male pores. 



