Fig. 165.—Phyllodoce paretti Blv. × ½. (From Règne Animal.)
In Eulalia an additional (fifth) tentacle arises from the middle of the back of the prostomium. E. viridis Müll. is a dark green worm smaller than the preceding; common between tide-marks, hiding in cavities and tunnels in limestone rocks, which have been bored by the mollusc Saxicava; it is rare where such rocks are absent. It might have been thought that its vivid colour would harmonise with its surroundings, but it is most abundant in regions where Fucus abounds and Ulva is absent. It is evident then that the colour is not protective; it may perhaps be of warning significance, for the mucus secreted in quantities by glands on the cirri of the Phyllodocids is probably objectionable to their enemies. Phalacrophorus Grf. and Pontodora Grf. may be mentioned as pelagic genera.
Sub-Fam. 2. Lopadorhynchina.—This includes small forms, Lopadorhynchus Gr., Pelagobia Grf., and other pelagic genera.
Fig. 166.—Nauphanta celox R. Grf. × 4. (From Greef.) e, The large eye.
Sub-Fam. 3. Alciopina.—These are surface forms, and, like most pelagic animals, are colourless and transparent; the eyes, however, are very large, and, with certain brown spots in each segment,[[377]] are the only coloured parts in the body; in structure the eyes are much more complicated than those of other Polychaetes. The prostomium has five tentacles; there are long peristomial cirri, and in general their anatomy agrees most closely with that of Phyllodocids. Alciope, Asterope, Vanadis, Nauphanta are genera of the family;[[378]] none have been recorded from the British area.
Fam. 5. Tomopteridae.[[379]]—This includes but one genus, Tomopteris, which is pelagic. The transparent, colourless body consists of only a few (eighteen to twenty) segments; the parapodia are as long as the body is wide, and carry no chaetae; each is bilobed, and fringed with a membrane; each of these lobes contains a yellow rosette-shaped photogenic organ. The only chaetae present in the worm are on the "head." The prostomium is hammer-shaped, and appears to carry a pair of short filaments ventrally (Fig. 167, x) each with a single chaeta within it; and a longer filament laterally (y), supported by a long, very delicate chaeta. The mouth is behind these, and they probably are the first pair of parapodia which have shifted forwards. T. onisciformis Eschscholtz is not unfrequently obtained off our shores in the tow-net.
Fig. 167.—Tomopteris rolasi Grf. × 10. From Guinea Isles. pr, Hammer-shaped prostomium; x, first chaetigerous process; y, second chaetigerous process; c, rosette (photogenic) organ on first two parapodia; b, similar organ in the lobes of the following parapodia; d, pigment spots; f, parapodium. (From Greef.)
Fam. 6. Nereidae (Lycoridae).—This family contains a very large number of species, differing from one another in small and not readily recognisable characters, such as the relative lengths of the various processes of the head, of the lobes of the feet, the arrangement of the "paragnaths" (see Fig. 125, d) and so forth. The general features of the family have been already described. The genus Nereis is represented by six fairly common species on our coast, which are almost world-wide in distribution.