igo8.] W. M1CHAE1.SEN : Oligochceta of the Indian Empire and Ceylon. 177 



External Characters. — Dimensions: lycngth 50 and 62 mm., greatest thick- 

 ness 2f and 3 mm., number of segments 86 and 95. 



Colour in general grey, at the anterior part of the body with a slight red- 

 dish tint, especially on the dorsal surface. The very slightness of pigmentation, which 

 distinguishes this species from other Perionyx species, seems to be a real character and 

 not merely caused by bad preservation. The specimens were prepared and kept to- 

 gether with specimens of another species, which had entirely preserved their brilliant 

 colouring. 



Head epilobous (about |). Hinder appendix of prostomium moderately broad, 

 open behind. 



Setae moderately large. Circles of setae nearly complete, only indistinctly inter- 

 rupted in the dorsal median line {zz = i-i^yz). Number of setae : 40-viii, 42-xxi. 



First dorsal pore in the intersegmental furrow 8-9, if not 7-8 or 6-7. 



Clitellum occupying segments 13 — 17 (=5), ring-shaped on segments 14 — 17, 

 interrupted ventrally on the 13th segment. 



Male pores (fig. 16) on the i8th segment somewhat behind the zone of setae, 

 distant one from the other about j of the circumference of the body, on small, 

 transversely oval papillae, which are somewhat inclined backwards. These papillae are 

 situated in the central depression of great, nearly circular, glandular protuberances, 

 which are bordered distinctly at the posterior edge, indistinctly at the anterior edge. 



Female pore in the median ventral line before the zone of setae of the 14th 

 segment, surrounded by an oval, nearly circular area, the longitudinal diameter of 

 which is a little longer than the transverse one. 



Spermathecal pores two pairs, in the intersegmental furrows 6-7 and 7-8, those 

 of one pair distant one from the other about I of the circumference of the body. 



Internal Anatomy. — Septa of the testicular region and some adjacent ones a 

 little thickened. 



Alimentary tract: A rudimentary gizzard, hardly broader than the adjacent 

 parts of the oesophagus and with hardly thicker walls in the 6th (?) segment. There 

 are no calciferous glands. 



Nephridial system meganephric. There seems to be no difference between 

 the nephridia of different segments (no alternation of length of the terminal duct as 

 in P. sansibaricus , MICHI^SN.). 



Anterior male organs: Two pairs of sperm-duct-funnels ventrally in the loth 

 and nth segments. These are apparently enclosed in unpaired testicular vesicles 

 which laterally are continued into great sperm-sac-like sacs. Three (?) pairs of sperm- 

 sacs (the foremost being a sperm- sac-like protuberance of a testicular vesicle ?) in the 

 loth, nth and 12th segments. 



Prostates with a small, rather compact, irregularly shaped glandular part on 

 a moderately thick, irregularly bent or coiled duct, which is about as long as the 

 glandular part. There are no penial setae. 



Spermathecae (fig. 17) : Main pouch with a big egg-shaped ampulla, which is 

 placed obliquely in regard to the axis of the duct. The duct of the main pouch is rather 



