418 Prof. Mluto.sli o?i (he 



it prol)aljly inhabits similar sandy flats at and beyond the 

 margin of low water on many shores — in company with 

 Valencinia armandi, Glycera, Aricia, Spio, Lanice concMlega, 

 and the crustacean and molluscan fauna characteristic of 

 such sites. 



It is a slender annelid, 150 mm. to 200 mm. in length, 

 pale pinkish anteriorly, dull greyish green (from the glands 

 of the digestive chamber) posteriorly. The snout is eyeless, 

 rennarkably flattened, translucent, and thinned at the edges, 

 like a pointed spatula. Behind, a constriction on each side 

 of the head a long tentacle occurs, the anteinor surface of 

 which has rows of elongated papillae of a somewhat cylindrical 

 outline. The segments of the body are numerous, and they 

 gradually diminish posteriorly and terminate in a broad 

 papilhi with a cirrus at each side, a little beyond the anus. 



The body is divided into two well-marked regions, in the 

 first of which (besides tiie head) are nine double pairs of 

 bristles, and in tliis respect it approaches the Heterospio 

 lonyissiina of Prof. Ebleis^, which also has nine anterior 

 segments. The inferior groups are simple, delicate, and 

 tapering, and they have a larger free portion and a more 

 pronounced terminal curve than the superior series. Both 

 have lateral expansions or wings, which, however, are wider 

 in the superior bristles and most pronounced posteriorly. 

 The latter are also more numerous. 



The ninth series of bristles has undergone special modifi- 

 cation. Each of the four broad fan-shaped groups consists 

 of slender translucent bristles with dilated tips and filiform 

 processes. The enlargement at the tip seems to be formed 

 by a modification of the wings, and various degrees of 

 development can be traced in tliem : thus in one of those 

 next the few simple bristles (with broad wings) which 

 correspond with the anterior tufts, the dilatation at the tip 

 being compaiativL4y slight. Next the foregoing a larger tip 

 is found, and then the well-marked series occurs, the axis or 

 shaft tapering to a fine point near the tip, Mhile the wings 

 continue as broad margins, and coalesce into the translucent 

 expansion with the filiform process. In the dorsal grou| s 

 there is only a tendency to the formation of the simple 

 bristles at each end of th ■ row, the rest consisting of those 

 with the enlarged translucent tips. The bristles of this 

 segment would appear to be honjologous with the special 

 forms in the third segment in Dlsoma, the fourth in the 

 CliEetopteridee, and the fifth in Pulydora, aud probably are of 



* Zeitscli. f. w. Zoj], Bd. x.w. p. CO. 



