580 Memoirs of the Indian Museum. [Vol. V 



it attains a relatively enormous size, and its length exceeds the width of the body. 

 It is traversed by three main blood-vessels, which give off numerous capillaries lying 

 beneath the cuticle. The dorsal spine emerges in a small papilla. In the posterior 

 feet the spines are only black near the tip. The falcate heterogomphs in the upper 

 group have rather longer and more spinous tips than those in the lower group. 

 There may be as many as three heterogomphs with coarsely serrated tips in the 

 posterior part of the lower group. The setae are fewer in the posterior segments. 



The anal segment is button-shaped, with very bright and conspicuous streaks 

 of reddish brown pigment. The anal cirri are as long as the posterior dorsal tenta- 

 cular cirri. 



The single specimen from the Cochin Backwater is 30 mm. long, consisting of 

 150 setigerous segments. The head, bases of the tentacular cirri, and anterior dorsum 

 are bright rusty red in colour. The middle region is reddish brown, and the posterior 

 region is bright red, especially in the lateral intersegmental areas. The anal seg- 

 ment is bright reddish brown. The tentacular cirri, feet, and ventral surface are 

 colourless, except near the tail, where the ventral surface is pale reddish brown. 

 The colour is due to granular pigment in the skin. 



The most striking difference in the feet of this specimen is the presence, with the 

 dorsal spine of the 10th to about the 60th foot, of a single slender hemigomph with 

 a long finely serrated tip (fig. 2j). The arrangement of the setae in the 10th foot is 

 shown in text-fig. 2c. The dorsal seta is guarded by a small fillet. 



The specimen from Garia, L,ower Bengal, is in bad condition, but resembles this 

 form in having a single hemigomph in the dorsal division of the foot. 



The head is similar in all the specimens, except that the tentacles and tentacular 

 cirri are shorter in the Cochin specimen. All were immature. 



This species is closely related to the Lycastis hawaiiensis, first described by 

 Johnson (1903, p. 210) whose specimens were found in a spring near Honolulu, Hawaii. 

 It was afterwards described by Horst (1909, p. 1), from specimens found in a fresh- 

 water pond in the Botanical Garden at Buitenzorg, Java. The Lycastis indica differs 

 from that species, as described by Johnson and Horst, in the following characters : — 



(1) the groove in the head ends in a pit, and does not run to the posterior border; 



(2) the eyes are almost in a line and are provided with lenses. According to John- 

 son, in the type the external pair are slightly in front of the internal pair, and have 

 no lenses ; (3) in the presence of much reddish brown pigment. Johnson says that 

 the only pigment present in his specimens was in the yellow tips of the posterior 

 dorsal tentacular cirri. Horst says: "The body of the preserved worms is quite 

 colourless, except the underside of the head and of two or three anterior segments, 



having a yellowish hue During life the worms appear to be flesh-coloured, due 



to the blood of the peripheral vascular system shining through the skin." (4) The 

 arrangement and structure of the setae differ considerably. Neither Johnson nor 

 Horst mentions the occurrence of the heterogomph setae with the long coarsely 

 serrated tips. According to Johnson, the setae are in two groups, the group above 

 the spine consisting of two or three moderately heterogomph setae (similar to the 



