1 92 1. J Fauna of the Chilka Lake : Polychaeta. 627 



Family GLYCERIDAE. 



Glycera alba, Rathke, var. cochinensis, var. nov. 



(Plate XXVII, figs. 17A-J, and text-figs. i6a-e.) 



Two specimens of this species were collected in the Cochin Backwater, near 

 Ernakulam. One of them is in good condition for description, the other is softened 

 and lacks the posterior region. 



This species closely resembles the European Glycera alba in appearance. The 

 preserved animals are buff coloured. The type specimen is 39 mm. long, and consists 

 of 120 setigerous segments. The body attains its greatest width between the 30th 

 and 40th segments. From this region it tapers abruptly towards the head, and only 

 very gradually towards the posterior end. On approaching the tail, however, it 

 decreases rapidly in size. The segments are biannulate, the two rings being almost 

 equal in length, or the ring bearing the feet is very slightly the longer of the two. 



The mouth (fig. 17A) is bounded laterally by two large tumid lips, formed of two 

 rings. In front of it are 10 rings which gradually taper towards the tip. The terminal 

 ring bears four small tentacles. The large segment which forms the posterior mar- 

 gin of the mouth is much folded ventrally, and bears a fairly large pair of parapodia. 

 In front of this segment are two others which are very narrow and incomplete ven- 

 trally. Each of them bears a pair of rudimentary parapodia, the anterior pair espe- 

 cially, being very small. 



The proboscis in both specimens is completely retracted, and the jaws lie opposite 

 the 21st pair of parapodia. The posterior part of the retracted proboscis is shown in 

 fig. 17B. The expanded part — the gizzard — containing the jaws, is almost square in 

 section, the rounded angles being formed by four large glands, whilst there is a smaller 

 gland on each face. Attached to the front margin of the gizzard are four flat, almost 

 rectangular lamellae, two directed forwards and two folded backwards. They are 

 composed of large rounded cells with large nuclei. 



The jaws (fig. 17E) are stout and curved. The fixing process is slender, and is 

 attached near the middle of the jaw. It bears a thin triangular wing on the basal part. 

 In the specimen figured, the posterior end of the jaw is bifid, but this is probably 

 due to fracture, as it is entire in other jaws which were examined. 



The internal surface of the retracted proboscis is covered with small papillae of 

 various shapes. The most numerous variety has a cylindrical stem (fig. 17c), with 

 an oblique mammillate tip, bounded by flat wings. The diameter of the stem is 

 equal to the width of the wings, and the papilla is 2\ times as high as the diameter. 

 Another variety is pear-shaped (fig. 17D), whilst others are similar in shape, but 

 slenderer. All are traversed by ducts opening at the tip. 



The ist foot is very minute, and consists only of a setigerous lobe with a group of 

 compound setae, and a flat heart-shaped posterior lobe. 



The 2nd foot is a little larger. The setigerous lobe has two bundles of compound 

 setae, an anterior finger-shaped lobe, and a posterior cordate lobe. 



In the 3rd foot, which is almost normal in size, there is a rounded dorsal cirrus, 



