ig2i.] Fauna of the Chilka Lake : Polychaeta. 593 



Habitat. — Twenty-six specimens were found in the four following localities : — 



Salt lake, Barantolla near Calcutta. Netted in 5-6 feet. 



Brackish pools near the Salt lake, Barantolla, November 1913. 



From mud in a ditch containing brackish water, at the edge of a salt lake at 



Dhappa, near Calcutta, January 1911. 



Burrowing in mud at Garia, Lower Bengal. 



These localities are all within 10 miles of Calcutta. The specific gravity of the 



water in which the specimens were found is very variable but never high, probably 



never exceeding i'Oi5. 



Nereis (Nereis) reducta, sp. nov. 



(Plate XXI, figs. 7A-7K, and text-figs. 6a-d.) 



Only a single specimen of this species was obtained, about one mile inside the 

 mouth of the Chilka Lake. The body is 50 mm. long, and is composed of 96 setiger- 

 ous segments. It is relatively narrow, and the ventral surface is grooved. The 

 segments are three times as wide as long in the anterior region, but the length 

 increases and the width decreases till they are less than twice as wide as long. The 

 body does not taper very much towards the posterior end. The head and dorsal 

 surface of the anterior segments are pale brown in colour ; the rest of the body is 

 colourless. 



The head (fig. y a) is narrow in front, broad behind, and the length slightly 

 exceeds the width. The eyes are small and distinct, with lenses. The palps are 

 large and pointed. The tentacular cirri are rather short, the posterior dorsal pair 

 being a little longer than the anterior dorsal. 



The proboscis of the unique specimen is fortunately fully extruded (figs, y a, ys). 



The paragnaths are distributed as follows : — 

 Group I A single large paragnath. Group J, > m . ^ 



II, 6 paragnaths of varying size. VI, > 



II, 6 paragnaths of varying size. 



III, 11 



IV. 8-10 



VII, ) Numerous paragnaths in 





VIII, y longitudinal rows. 



The paragnaths of the distal or maxillary segment are of the normal dark conical 

 type (fig. 7c). Those of the basal segment are small, flattened, and circular, of a 

 pale amber colour (fig. 7D). The dorsal group consists of two paragnaths close 

 together in the median line, and may both be in Group V, or one each in Group VI. 

 They are very minute, and easily overlooked. The ventral Groups VII and VIII 

 occupy a large area, and are composed of numerous longitudinal rows, each contain- 

 ing 4-7. minute paragnaths. 



The jaws are provided with 7 or 8 teeth. 



The feet gradually increase in size up to the 6th. 



The ist foot (fig. 7E, and text-fig. 6a) as usual, is represented by the ventral 

 division, the dorsal cirrus and a lobe between them. This latter lobe, as a considera- 

 tion of figs. 7E, 7F, and yQ clearly shows, represents the median ligule. The dorsal 

 and ventral cirri are rather short and finger-shaped, the median and lower ligules 



