THE BRISTLE-WORMS. 101 



bility. Thus, to take one example only, it is believed by 

 some authorities that there are two "paddle-worms," one 

 called P. lamelligera and the other P. laminosa, while 

 others maintain that these two are one, or are mere varieties 

 of one species. The curious point is that those who regard 

 them as distinct are by no means agreed as to the dis- 

 tinguishing features of each, a fact which certainly suggests 

 the occurrence of variation. Other authorities believe that 

 very many of the so-called " species " of Phyllodoce are mere 

 varieties, and that one may, as it were, pick out a few 

 dominant types, round each of which a number of more or 

 less clearly defined varieties group themselves. The point 

 is a very interesting one. 



The next genus Eulalia differs from Phyllodoce in the 

 presence of an additional tentacle, so that the head bears 

 five instead of four of these. Curiously enough, however, 

 apart from this prime difference, there is an extraordinary 

 parallelism between the " species " of Eulalia and the 

 "species" of Phyllodoce. Thus there is a species of Eulalia 

 which, except for its tentacle, resembles in almost every 

 respect Phyllodoce maculata, while our commonest Eulalia 

 (E. viridis) has a twin brother in a green Phyllodoce. As 

 the extra tentacle in Eulalia is often by no means easy to 

 see, there is no difficulty in understanding that this fact has 

 tended to add greatly to the confusion of nomenclature and 

 description, so that the Phyllodocids in general form a very 

 difficult family, and one in which there is still much to be 

 done. 



We shall only describe one species of Eulalia, and that is 

 the common and beautiful E. riridis, the green leaf-worm. 

 It is a small w T orm, three inches or less in length, of a bright 

 green colour, which is peculiarly vivid in females filled with 

 eggs. It is common in rock crevices at many parts of the 

 coast, and is readily recognised at a glance as a Phyllodocid 

 from the green leafy plates which in life are in constant 

 movement. The fact that it is a conspicuous worm and 

 lives considerably above low-tide mark makes it the most 

 obvious of the Phyllodocids, for P. lamelligera is local and 

 P. maculata is so slender and inconspicuous as to be readily 

 passed over without notice. In spite of its beauty and 

 fragile appearance, Eulalia, like the other Phyllodocids, is a 



