FAM. 9. _Eunicidae._—The elongated body is provided with parapodial gills in more or fewer segments (except in _Lumbriconereis_). The "gills" may be cirriform (_Hyalinoecia_), pectinate (_Eunice_, _Onuphis_), or more complex (_Diopatra_). The notopodium is represented by a lobe (usually called "cirrus") into which an aciculum projects; in some cases it even contains a few chaetae; most of the neuropodial chaetae are jointed (Fig. 138, F). The prostomial tentacles vary in number; they may be three or five, or five and two short "frontal palps," or they may be absent. Peristomial cirri are absent, though in _Eunice_, _Diopatra_, and _Onuphis_ "nuchal cirri" are present on the dorsal surface of the second segment (Fig. 134, D). One of the most characteristic features in the anatomy of the Eunicids is the peculiar jaw apparatus (see p. 270). The majority of the genera form permanent tubes of parchment-like consistency, {319}which may be further strengthened by the addition of grains of sand, small pebbles, etc.; the tubes may be branched. _Eunice_ has five tentacles, two great palps, and a pair of nuchal cirri; the gills are pectinate, and there are four anal cirri. _E. harassii_ Aud. and Edw. is about 8 inches long. It is reddish-brown, with white spots down the back, one to each segment, and others at the sides. The gills begin at the sixth segment, and when fully developed have eleven branches. The dorsal cirrus is not longer than the gill. _E. philocorallia_ Buch.[381] forms its tube amongst the branches of _Lophohelia prolifera_, in 200 fathoms, off the west coast of Ireland. _Marphysa_ resembles _Eunice_, but has no nuchal cirri. _M. sanguinea_ Mont. is a fine bronze colour, with bright red gills, which commence on the twentieth segment, and have only four or five branches. The worm, which measures 12 to 18 inches, and is as thick as one's finger, hides in clefts in rocks and under stones below low water. Mediterranean. It is known as "Rockworm" in the Channel Islands. _Hyalinoecia_ Mgrn., in addition to the five prostomial tentacles and palps, possesses a pair of small "frontal palps" arising from the anterior border of the prostomium; there are no nuchal cirri, and the gills are simple filiform processes. _H. tubicola_ Müll., about 3 inches long, is yellowish-brown, and forms a transparent, parchment-like tube. Atlantic and Mediterranean. [Illustration: FIG. 170.—_Ophryotrocha puerilis_ Clap., Metsch. × 25. _ci_, Bands of cilia; _cp_, ciliated pit (nuchal organ); _J_, jaws. (From Korschelt.)] _Onuphis_ Oerst. has a head like the preceding, from which it differs in having pectinated gills and two nuchal cirri like _Eunice_. In making its tube it employs small pebbles, bits of shell, and even echinid spines, which it glues together with mucus, so that it bears a general resemblance {320}to its surroundings. _O. conchylega_ Sars, has a flattened, scabbard-like tube, which can be carried about by its owner. Atlantic.