1921.] 



F anna of the Chilka Lake : Polychaeta. 



613 



of slender spines running into its base, but not piercing the skin. In the four ante- 

 rior pairs of feet the setigerous lobe is relatively much larger than in the others. 



The ist foot (fig. 14E, and text-fig. 12a) has a large fusiform lobe behind the 

 setae. In front of it lie two low rounded papillae, the dorsal one being the larger. 

 A single capillary seta emerges behind the dorsal papilla. Ventrally there are 4 bifid 

 hooks, 2 thin ones in front of the ventral papilla, and two thicker ones between the 

 two papillae. In addition there are many stout and slender setae in the setigerous 

 lobe and in the base of the dorsal cirrus which do not pierce the skin. In the bifid 



(I 



Text-fig. 12. — Parapodial diagrams of Diopatra variabilis, sp. nov. 



a. ist foot ; b. 10th foot ; c. 20th foot, setigerous lobe only shown ; d. 70th foot ; e. 150th foot. 



— = dorsal capillary setae, without wings, in segments 1-4; x = bifid setae in segments 1-4; •; =spines or setae 



of varying thickness, which are embedded in the tissues and seldom pierce the skin ; o = brush setae ; I = capillary 



setae, winged and smooth in anterior segments, serrate in posterior segments; v= ventral capillary setae, with flat 



smooth wingless blades ; A == stout ventral hooks of middle and posterior segments. 



setae (fig. 14M) the tip is enclosed between two wings, and the shaft is obliquely 

 striated. A short distance behind the tip there is in some cases a pseudo-articulation. 

 The dorsal capillary seta is strong, broad, curved, and finely pointed, with smooth 

 edges. The blade is flattened, but not winged. 



The 2nd and 3rd feet are similar in shape, with two dorsal capillary setae, three 

 stout bifid setae between the anterior papillae, and two thin ones in front of the 

 lower papilla. The posterior lobe is rather more elongate than in the ist foot. On 

 the 4th foot is the first branchia, rather shorter than the dorsal cirrus. The rest of 



