332 



POLYCHAETA 



is very obscurely marked, for internally there are only three 

 complete septa, placed far forwards. The intestine is bent upon 

 itself. In Ophelia limacina Ethk. the gills commence in the 

 eighth segment, and the longitudinal ridge does not extend in 

 front of this segment. The worm is about 1^ inches long, and 

 occurs between tide-marks. Travisia forbesi Jnstn., Xorth Sea. 

 Polyophthcdmus pictus 1 Duj. is very abundant at some parts of 

 the coast. There are two bundles of chaetae on each side of 

 every segment ; each bundle contains three chaetae, of which only 

 one projects to any distance. Paired eye-like spots exist on the 

 sides of twelve segments. The worm is about an inch in length. 

 Fam. 2. Mcddanidae ( = Clymenidae). Eepresented on our 

 coasts by four fairly common species. They form sandy tubes, 

 which are embedded in the sand with a short portion projecting. 

 In some places they are so abundant that at low water the sand 

 has quite a rough appearance. The prostomium is frequently 

 truncated and depressed, and is always fused with the peristomium. 

 A horny plate may be developed on the upper surface of the head, 

 and the skin at the side of the prostomium is 

 frequently raised into a more or less prominent 

 fold. The hinder end of the body carries a 

 funnel surrounding the anus. There are no gills 

 or sensory processes on the body. Some of 

 the segments towards the middle of the body 

 may be longer than the rest. Peculiar serrated 

 hooks of characteristic shape constitute the neu- 

 ropodial " torus." The buccal region is eversible. 

 Nicomaclie lumbricalis Fabr. is a rosy-pink 

 worm with white spots anteriorly ; the chaetigerous ridges are 

 red. The worm consists of twenty-six segments, and measures 

 2 or 3 inches. It is very narrow and readily breaks in pieces. 

 The prostomium is laterally compressed ; the anal funnel is 

 fringed with a number of short equal processes. Under stones in 

 the Laminarian zone. 



Axiothea catenata Mgrn., which may reach a length of 3 or 

 4 inches, resembles the above in general colour, though of a 

 deeper tint. There are only eighteen chaetigerous segments. 

 The head has a membranous fold of skin on each side, and the 

 anal funnel is produced into longer and shorter processes. Both 



1 Ed. Meyer., Arch. mikr. Anat. xxi. 1882, p. 769. 



FIG. 178. Anal fun- 

 nel of Nicomache 

 lumbricalis. 

 (From Malm- 

 gren. ) 



