1921.] 



Fauna of the Chilka Lake : Polychaeta. 



619 



of the dorsal setae. They have expanded oblique tips, with numerous fine teeth, of 

 which the two outermost are much longer and stronger than the others. At the 

 35th foot a powerful hook (fig. 131,) appears on the lower edge of the ventral setae. 

 It is bifid at the tip, but in the anterior segments the points are either rounded or 

 worn away. The tip is guarded by two delicate flexible wings, and the shaft is finely 

 dotted. 



The 40th foot (fig. 13F, and text-fig. 13c) has 3 or 4 spines, the upper one being 

 colourless. The dorsal and ventral cirri are relatively smaller than in the ist foot. 

 In segments 50-120 there are two ventral hooks. 



Text -fig. 13. — Parapodial diagrams of Murphy sa gravelyi, sp. nov. 



a. 2nd foot; b. 5th foot; c. 30th foot of small sp., 40th foot of large sp. 

 small sp., 240th foot of large sp. 



■ = capillary setae ; • = spines ; x = compound setae ; > = simple bifid hook. 



d. 160th foot of 



After the 100th foot, capillary setae appear in the ventral bunch, replacing the 

 compound setae. A single compound seta remains in many feet, at the upper ante- 

 rior border of the ventral bunch (text-fig. 13d), but the posterior 100 feet have no 

 compound setae. At the 240th foot (fig. 13G, and text-fig. 13d) the branchia has its 

 maximum of 9 filaments. The dorsal cirrus is short and conical, the ventral cirrus 

 stumpy and round. The middle papilla is very small, and the internal fillet runs out 

 to the tip of the black spine or spines. The external fillet now runs completely 

 round the setigerous lobe. The dorsal division has 4 brush setae in front, arranged in 



