448 MARPHYSA BELLI. 



4 mm. long, simple branchiae appear on the tenth setigerous segment. In the larger 

 examples (10 to 20 mm.) the eyes are always two, and the branchiae commence on any 

 segment between the tenth and twenty-third (as in the adult), and they are usually 

 bifurcate. The dental apparatus of these, according to the author, agrees with that in 

 the adult. The brush-shaped bristles do not occur in the youngest forms, or until three 

 tentacles and branchiae are present. If the author is accurate in his diagnosis, the 

 younger forms resemble Nematonereis. The same author mentions that in those from 

 New Jersey the branchiae commence on the tenth foot — a considerable variation from the 

 usual condition in Britain. 



Cosmovici l describes the segmental organs of this species as consisting of a 

 ciliated funnel in the dissepiment in front, and a tube leading externally at the base 

 of the foot. 



Mr. Borradaile 2 gives an interesting account of the early stages in the development 

 of a Ceylonese Marphysa. The yellowish eggs are in an oval mass of mucus with a stalk, 

 and he found that the larvae, after escaping from this, afterwards secreted another mucus 

 investment in which they lived gregariously. 



Benham states that it is the " rock-worm " of the Channel Islands. 



Grravier 3 (1909) describes an instance of reproduction of head and anterior segments 

 and tail in an example of this species from St. Vaast-la-Hougue. The tapered anterior 

 end is conspicuous. 



2. Marphysa Belia, Audouin and Edwards, 1833. Plate LV, fig. 5 ; Plate LV, fig. 6 — foot ; 

 Plate LX, fig. 12— head; Plate LXIII, figs. 2 and 2 a— teeth ; Plate LXV, figs. 

 11 and 11 a— teeth; Plate LXXXVI, figs. 3 and 3 d— bristles. 



Specific Characters.— Head bluntly conical, with a median groove inferiorly, but 

 evenly rounded in front, only a slight notch appearing in spirit. Tentacles proportionally 

 long and slightly crenate. Body 6 — 7 ins. long, and attenuated for a Eunicid. It is 

 somewhat reddish anteriorly, fawn coloured posteriorly, with a dark purple central streak 

 from the blood-vessel. It is highly iridescent throughout. Peristomial segment twice 

 the breadth of the others, that following being about the average breadth. Proboscis, 

 armed with maxillae which rise little above the horizontal, are blackish-brown anteriorly 

 and greyish or pale chocolate at the base. Basal processes foot-shaped with a terminal 

 point. Great dental plates have seven teeth, the azygos plate on the left has seven or 

 eight teeth, the curved plate in front about six teeth. The right anterior curved plate 

 has seven to eight teeth. The mandibles have black tapering shafts, and the cutting 

 anterior edo*es are sinuous. Branchiae commence on the fourteenth foot and continue to 

 the thirty-fourth or a little further, and thus range from twenty to twenty-five in number. 

 The central stems have most filaments, the first having about ten, the twenty-eighth 



1 ' Thesis/ p. 114, pi. xxvi, fig. 7. 



3 < Proc. Zool. Soc./ 1901, vol. ii, p. 714, pi. xxxix. 



3 ( Ann. Sc. nat./ 9 e ser., t. ix, p. 150, 1 text-fig. 



