1921.] Fauna of the Chilka Lake : Polychaeta. 623 



The body is very slender, the greatest width being 1 -0-1-2 mm., not including the 

 feet. It tapers very gradually towards the tail, more rapidly, but to a lesser degree 

 towards the head. The skin of the preserved specimen is opaque white in colour, 

 with a faint green iridescence. 



The head (figs. 15A, 15B) is rounded in front and at the sides. Dorsally the 

 posterior border is covered by the projecting front border of the peristomium. No eyes 

 were observed, though there is a 

 small patch of pigment near the 

 posterior border of the head, a 

 little on the right of the median 

 line. The mouth is bounded in 

 front and at the sides by two 

 large lips formed by the infold- «^ 



ing of the lateral posterior mar- Text-fig. 14. — Parapodial diagrams of Lumbriconereis 



polydesma, sp. nov. 

 gins of the head. Between the fl Istfoot; b Iothfoot . c . 8oth foot . 



head and ISt SetigerOUS Segment • = Simple capillary setae ; x = crochets. 



are two achaetous rings, the first 



being twice as broad as the second. Ventrally the ist ring is incomplete, being 

 interrupted by a projecting lobe of the 2nd ring. Both rings are furrowed on the 

 ventral side. 



The feet increase gradually, and only very slightly, as far as the 10th. The ist 

 foot (text-fig. 14a) has a prominent rounded ventral lobe. The setae lie above and in 

 front of this lobe, and are guarded externally by a conspicuous curved fillet. There 

 are two colourless spines. The setae are stout winged capillaries, with bilimbate 

 obliquely striated blades. There are 3 of them above the spines and 4 below. 



In the 10th foot (fig. 15F and text-fig. 14b) the fillet forms a hood over the 

 ventral lobe. It is attached to the middle of it in front, then curves over it, and is 

 attached to it again on the lower posterior border. There are 3 spines in a horizontal 

 row. They are colourless, except the tips of the two anterior ones, which are dark 

 brown. There are 4 capillary setae above the spines and 5 below. The upper setae 

 are rather longer than the lower, and they all curve towards the spines. 



At the 29th foot the first crochet appears in the ventral division. The 30th foot 

 has 2 colourless spines, 3 capillary setae above the spines, 2 capillary setae and 1 

 crochet below the spines. The fillet lies more in front of the ventral lobe than in the 

 10th foot, and its anterior line of attachment is near the ventral border of the lobe. 



The 40th foot is similar in shape. It has 2 spines, 2 capillary setae and 1 crochet 

 above the spines, 1 capillary seta and 2 crochets below. 



In the 80th foot (fig. 15G, and text-fig. 14c) the ventral lobe is smaller and 

 slenderer, and curves upwards. The fillet lies almost altogether on the anterior side 

 of the lobe, and is hardly visible from the posterior aspect. There are 2 spines, 1 

 capillary seta and 1 crochet above the spines, 3 crochets below. 



The shape of the feet is very uniform in the middle and posterior parts of the 

 body. At the 300th foot (fig. 15H) the ventral lobe is rather longer and thinner. 



