434 OLIGOCHAETA 



he proposed to include in a new genus, Pleionogaster. I have already (p. 365) 

 discussed the genus. The species are all from the Philippines, and may be thus 

 distinguished : — 



Gizzard well developed P. horsti. 



Gizzard more or less rudimentary: 



Four accessory gizzards P. jagori. 



Three accessory gizzards P. samarieusis. 



(i) Pleionogaster horsti (Beddaed). 

 Perichaeta horsti, Beddaed, P. Z. S., 1886, p. 300. 



Definition. Length, 73 mot.; breadth, 4mm.; number of segments, about 300. Setae, 67 

 in segment II ; tJience increasing up to segment VI (151)^ gradually diminishing to 

 72 in segment XII ; in hinder region of body only 52 per segment. Glitellum, XIY-XVII ; 

 continuous rings of setae on all its segments. Dorsal pores present. Three papillae, one 

 median and two lateral, on segments XVI, XVII, XIX, XX, XXI, and XXII. On XVIII 

 median papilla alone present ; male pores occupying the position of lateral papillae. 

 Gizzard in VIII; oesophagus from IX— XVI, with much-folded and vascular walls; 

 intestine begins in XIX; in segments XXVI-XXVIII (about) three accessory gizzards. 

 First septum, IV/V; four following greatly thickened. Spermathecae in VIII and IX, 

 with a short tubular diverticulum. Hab. — Neighbourhood of Manila. 



(a) Pleionogaster jagori, Michaelsen. 



p. Jagori, Michaelsen, Arch. f. Nat., 1892, p. 247. 



Definition. Length, \']omm.; breadth, i^mm.; number of segments, 270 [about). Setae very 

 numerous on anterior segments: 150 on X; only 84 on XXI. Glitellum, XIV-XVII ; 

 on the last segment only, on upper side of body. Dorsal pores commence XII/XIII. Male 

 pores separated by two setae ; two pairs of genital papillae on intersegmental furrows 

 XVII/XVIII, XVIII/XIX, on a level with the male pores. Gizzard in VIII; accessory 

 gizzards, four in segments XXVII-XXXIII. The anterior septa, as far as, and including, 

 VIII/IX, thickened. Sperm-sacs in XI, XII. Spermathecae as in last species. Eab. — 

 Daraga, Luzon. 



(3) Pleionogaster samariensis, Michaelsen. 

 p. samariensis, Michaelsen, loc. cit., p. 248. 

 Definition. Length, 'j^mm.; breadth, o,mm.; number of segments, 230. Setae, 160 on X; 



