POLYCH^ETA SEDENTARIA OF THE FIRTH OF FORTH. 655 



Eumenia crassa, Oersted. 



Polyphysia crassa, Quatrefages, Armeies, ii. 



Eumenia crassa, Oersted, Ann. Dan. Consp. Arch. f. Naturges., x. 1; Sars, 



Nyt. Mag., vii. 12 (description) ; Johnston, Cat. Brit. Mus.; Malmgren, 



Ann. Polychaet.; M'Intosh, Fauna of St Andrews. 



The body is cylindrical, the thickest part near the anterior end. The first 

 six chaetiferous somites bear branchiae in the form of a thick cluster of 

 papillae sprouting from a central stem, and situated in front of the notopodium 

 (PL XLIL fig. 18 a). Each division of the parapodium consists of a pointed 

 lamella towards the outside of the parapodium, and a fan of simple acicular 

 chsetse towards the centre of the same. Such parapodia are present on all the 

 somites except the buccal and anal. The anterior end is conical, terminating 

 in two small divergent points ; the anal segment is without appendages. 



Habits. — Dredged in the Firth. 



Lipobrancliius, n. g. 

 Lipobranchius Jeffreysii (M'Intosh). 



Eumenia Jeffreysii, W. C. M'Intosh, On the Structure of British Nemer- 

 teans, and some new British Annelids, Trans. Roy. Soc. Edin., 1868. 



This worm we have not examined in detail : it evidently belongs to the 

 family Scalibregmidse, being similar in many respects to Eumenia, in which 

 genus M'Intosh placed it. We have formed a new genus for it on account of 

 the entire absence of branchiae or branchial cirri. It is fusiform, both ends 

 being conical, and it is not easy at first to distinguish which end is anterior 

 and which posterior. The worm, in fact, looks like a maggot. Parapodia are 

 present on all the somites except the buccal and anal, and are all similar in 

 structure. Each consists of two similar mammillate processes bearing a few 

 small chaetae at the apex. The ventral body-wall is much more muscular 

 than the dorsal, and in spirit the former is contracted so that the body is 

 curved (PI. XLIL fig. 19). On each somite there are about three transverse 

 corrugated ridges, but there are no definite constrictions between adjacent 

 somites, which are only indicated by the parapodia. 



Large numbers of specimens of this form were dredged in several places 

 in the Clyde by the "Medusa." The worm is found only on muddy bottoms, 

 and lies enclosed in a thick tube formed from the mud hardened by an 

 excretion from the skin. 



M'Intosh says the chaetae are of two kinds — one kind simple, the other 

 bifurcated into two large branches. He also says there are two short thick 

 tentacles on the head, and several elongated processes round the anus. We 



