POLYCII.^TA. — ^BENHAM. 231 



in length, with a dir^nieter of 6 mi a. at its widest ; across the 

 feet it measures 9 mm., and the height is 6 mm. The body 

 is convex dorsally and flat ventrally. 



The segments are very short, being about one-tenth of 

 the diameter of the body, and separated by deep furrows. 



The worm contains 247 segments, tapering forward, from 

 the 25th to a diameter at the peristomium of only 2-5 mm., 

 and posteriorly where the last segment is 1 mm. in diameter. 

 Its colour is brown, without any iridescence. 



A second complete specimen measures 120 by 5 mm. ; 

 the jaws are jjartly protruded, and the appearance of the 

 head from above recalls the drawing given by Savigny of 

 0. Ivcida. 



A third, fragmentary, is 50 by 5 mm. ; the head is much 

 retracted ; and a fourth consists of head and 70 segments 

 measuring 80 by 5 mm. 



The prostomium is a bluntly rounded cone ; its length is 

 equal to its breadth ; it carries three minute conical ten- 

 tacles, hidden under the overhanging anterior margin of the 

 peristomium (PI. xliii., figs. 95, 96). 



There are two pairs of eyes, the anterior larger, leather 

 lateral in position and oval in shape ; the posterior small, 

 admedian and round, lying in front of the bases of the two 

 admedian tentacle-, and, like them, hidden. 



It was not until I had slit open the dorsum, in order to 

 study the jaws, that I detected the tentacles, but having 

 discovered them, I found it possible to see their tips in other 

 specimens, on forcing back the peristomial margin. 



The under surface of the prostomium has a very deep 

 median groove, which widens outwards posteriorly. There 

 are no '' palps '" (PI. xliii., fig. 97). 



The peristomium (the only footless segment) is, on its 

 dorsal surface, but little k)nger than the first chsetigerous 

 segment, but on the ventral surface it lengthens out pos- 

 teriorly, so that in the mid -line it is about twice the length 

 it has laterally. The median region, forming the lower lip, is 

 marked oiit from the lateral by a pair of longitudinal furrows, 

 starting from the anterior margin, and then curving outwards 

 to die out. There is a slight median notch, which, however, is 

 better seen in a specimen in which the prostomium is re- 

 tracted, and therewith the peristomium stretched. 



The sides of the peristomium are somewhat grooved, and 

 these also are obliterated when the prostomium is retracted. 



