278 Memoirs of the Indian Museum. [Voi,. I, 



movement, as in other species of the genus; backward progression is effected by a 

 series of jerks, as in the Naididae. 



The prostomium is large, rounded, flattened, broader than the body, very mobile, 

 and continually altering its shape ; its ventral surface is ciliated ; no special ciliated 

 pits were observed. The oesophageal region, which succeeds the buccal funnel, is 

 followed by the region of the stomach, where the diameter of the body is greater 

 than at other parts ; the region of the stomach may be said roughly to comprise 

 the middle third of the animal ; behind it, the diameter gradually diminishes to the 

 posterior end. 



The oil-drops, which occur in the integument over the whole body, are of a 

 bright brownish-red or very deep orange colour. They vary in size, and there is 

 always a special aggregation of very large droplets at the extreme posterior end of 

 the animal; the single drops may here reach "01 mm. in diameter, or about one-fifth 

 of the width of the animal at this part (figs. 53 — ^55). Over the remainder of the 

 body they vary from -006 mm. downwards. They are absent from the under 

 surface of the prostomium. They lose their colour soon after the death of the animal. 



The number of segments of the single animal varies from eight to eleven. 

 Specimens preparing to divide asexually contained seven or eight segments in the 

 anterior, six or seven in the posterior half. Elongated chains of three, four, or more 

 animals have not, so far, been met with. 



The setœ are arranged in four bundles per segment, two dorsal and two ventral, 

 beginning just behind the posterior end of the buccal funnel. They are almost 

 straight, sometimes very slightly bowed or j -shaped. They are all capilliform, 

 and vary in length, being usually about equal' to the diameter of the body. The 

 number in each bundle varies from two to five. 



There are no definite septa, but strands stretch across the body-cavity from 

 body-wall to alimentary tube ; these are more numerous at the site of an approaching 

 division. Some large body-cavity corpuscles were seen on one occasion, possibly 

 broken off from the sides of the alimentary canal (c/. the large cells, c, in fig. 55). 



The buccal funnel has a thick, prominent rim, the lateral limbs of which bend 

 outwards at their dorsal and anterior ends (fig. 53, r.). Ciliary motion is markedly 

 visible in the interior of the funnel. The oesophagus occupies the second and third 

 segments, the stomach the fourth, fifth and sixth. The stomach has thicker and more 

 granular walls than the rest of the tract, and its calibre is greater ; its walls are 

 ciliated ; the cilia move in an antero-posterior direction sometimes, sometimes in the 

 posterior half in the reverse direction, and sometimes the motion is not definitely 

 in either direction. 



The case is different in the intestine, where the ciliary action is always poster o- 

 anterior; it may be very violent and distinct, so as to be visible with the low power 

 of the microscope. The intestine also exhibits the same '' antiperistaltic" movements 

 that are such a marked feature in the Naididae ; these may extend as far forwards 

 as the anterior end of the stomach; or may, for a time, be confined to the stomach; 

 or, as in one case observed, there may be an antero-posterior peristaltic movement 



