1921.] Fauna of the Chilka Lake : Polychaeta. 653 



composed of the no segments, and the anal segment is large and conical. The 

 posterior 15 segments are mnch shorter than the preceding ones, and may have been 

 regenerated. 



There are seven pairs of branched gills, unconnected by a membrane (fig. 26A). 

 Each gill is penetrated by a single blood-vessel (fig. 26c), which sends off a single 

 branch to each barbule. The barbules are rather short, and the distal quarter of each 

 gill is devoid of them. In addition there are two smooth unbranched ventral tentacles, 

 or palps. 



The upright collar is equal in length to the ist setigerous segment. On the 

 dorsal side (fig. 26A) the two halves of the collar are simply folded inwards, and 

 attached to the body wall. On the ventral side (fig. 26b) the collar projects forwards 

 in two peculiar lobes, each pointed at the tip. Between these two lobes and the 

 palps is a median lobe rounded at the tip. No eyes or otocysts were observed. 



The thorax is composed of six setigerous segments. Along the median dorsal 

 line there is a narrow groove, which passes to the ventral side in the 6th setigerous 

 segment, and runs to the posterior end. Ventral thoracic gland plates are incon- 

 spicuous or absent. The ist thoracic segment bears only dorsal bundles of setae, 

 which lie nearer the median line than those of the succeeding segments (fig. 26A.) 

 The setae are all capillaries, mostly long and slender, with narrow bilimbate blades. 

 A few are shorter, with relatively broader blades. In the 2nd segment the dorsal 

 setae are of two kinds. The upper setae are long slender capillaries (fig. 26D), 6 or 8 

 in number, with narrow wings and long tapering tips. Below these are 9-1 1 setae 

 with spatulate tips (fig. 26K) terminating in a long fine point. The ventral setae 

 consist of a row of 20 uncini (fig. 26G). Bach of the latter has a stout rounded 

 base. In front view (fig. 26G, a) there are 4 or 5 rows of teeth on the crest above the 

 main fang. The side view (fig. 26G, b) shows that the main fang is very acute, with 

 4 teeth above it. The remaining thoracic segments, 3-6, have similar setae. 



Of the abdominal setae those on the 8th setigerous segment may be taken as 

 typical. The dorsal division consists of 17 uncini (fig. 26H) differing only very 

 slightly from those of the thorax. The rounded base is rather more oblique, and 

 the gap between it and the main fang is larger. The ventral group contains 4 or 5 

 capillary setae (fig. 26F). The expansion formed by the wings is shorter and broader 

 than in the thoracic setae, and the tip is long and slender. 



In the posterior segments the setae are similar in shape, but the capillaries are 

 rather longer. Nothing is known about the tube of this species. 



Habitat. — A single specimen was taken in the south-western extremity of Chilka 

 Lake, 1-8 miles N.W. by N. of Sanad Point. The specific gravity of the water was 

 1*009 during the salt-water season. 



Fabricia (Manayunkia) spongicola, sp. nov. 



(Plate XXXI, figs. 29A-E.) 



A number of specimens of this species are available, in a rather contracted 

 condition. They inhabit tubes, consisting of a delicate membrane covered with 



