IQ2I.] 



Fauna of the Chilka Lake : Polychaeta. 



579 



The feet increase in size up to the 7th pair. The two anterior feet differ from 

 those of most species of the Nereidae in having a dorsal spine present. 



The ist foot (fig. 2B and text-fig. 2a) has a short stumpy dorsal cirrus, jointed 

 at the base, and is shorter than the finger-shaped ventral cirrus. The setigerous 

 lobe is broad and truncated, with a papilliform retractile tip. The dorsal division is 

 only represented by a black spine. The ventral setae are in two groups, one above 

 and one below the spine. The upper group, emerging from the front of the foot, 

 consists of two setae, one a short falcate heterogomph (fig. 2F), the other a hemigomph 

 with a long finely serrated terminal piece (fig. 2G). The lower group consists of 

 heterogomphs, the upper posterior one having a long finely serrated terminal piece, 

 the others short falcate tips. 



In the 2nd foot the dorsal cirrus is larger than the ventral. The upper group of 



o O 



o 



o 



o 



a/ h c 



Text-fig. 2. — Parapodial diagrams of Lycastis indien, sp. nov. 

 a. ist foot of specimen from the Behaghatta Canal. 

 . i. oxn ,, ,, , , , , ,, j, 



c. 10th ,, ,, ,, ,, Cochin Backwater. 



d. 70th ,, ,, ., >, Beliaghatta Canal. 



• = Hemigomph setae with long finely serrated tips ; x = Heterogomph setae with falcate tips : 

 gomph setae with finely serrated tips ; o = Heterogomph setae with coarsely serrated tips. 



— = Hetero- 



setae consists of two hemigomphs with long finely serrated tips, and two falcate 

 heterogomphs. The 3rd foot is similar, the dorsal cirrus being a little larger. 



In the 10th foot (fig. 2C and text-fig. 2b) the upper group consists of three 

 anterior falcate heterogomphs and three posterior hemigomphs with finely serrated 

 tips. In the lower group the upper posterior seta is a heterogomph with a long tip 

 which has very coarse serrations on its lower edge (fig. 2h). This has replaced the 

 finely serrated heterogomph of the anterior segments. Beneath it are 4-7 falcate 

 heterogomphs. The dorsal cirrus is jointed, with a cylindrical base, and the appa- 

 rent increase in size of the dorsal cirrus in this and the succeeding segments is due to 

 the enlargement of the base, which carries the dorsal cirrus at its tip. 



In the succeeding feet there is little alteration, except as regards the gradual 

 enlargement of the base of the dorsal cirrus (figs. 2D, 2E and text-fig. 2d). This 

 enlargement is greatly accentuated about the 60th foot. In the posterior segments 



