126 POLYMNIA NESIDENSIS. 



posterior. Lateral lobes on the anterior segments. Branchiae, three. The (smooth) 

 bristles begin on the fourth segment. Hooks, which commence on the fifth segment, 

 with one or two teeth above the main fang; the basal region elongated and convex 

 interiorly. The nephridia are separate from each other, and are somewhat short and 

 wide, those of the fifth segment having a longer tube (Hessle). 



1. Polymnia nesidensis, Belle Chiaje, 1828. Plate CXIV, fig. 6— body ; Plate CXXVa, 



figs. 5 — 5 b — bristles and hook. 



Specific Characters. — Cephalic collar less developed than in T. nebulosa. Upper 

 lip large and frilled, and lower lip prominent, with a tongue-like process internal to 

 and above the latter. Eyes are absent in many preserved examples, but others show 

 numerous eyes behind the dorsal collar. Body rather small (40 mm. in length), 

 terminating posteriorly in the vent, which has two longer median and two lateral cirri 

 on the ventral surface. Segments 50 — 80 two-ringed ; two or three behind the buccal 

 have lamellae at their outer edges ventrally and opposite the first and second branchiae. 

 Fifteen to sixteen ventral shields. 1 Branchiae three, the first the larger, dichotomously 

 branched with short terminal divisions, so that the tips appear to be evenly truncated. 

 Setigerous processes seventeen, the first close to the last branchia. Bristles in two series, 

 a longer and shorter, the former with broader wings. Rows of hooks commence on the 

 second bristled segment, a single row anteriorly, but a double row in segments 11 — 20. 

 The hooks are distinguished from those of T. nebulosa by the presence of a second tooth 

 above the great fang. Body and tentacles yellowish, dorsum brownish, or occasionally 

 dull greenish. Nephridia occur from the third to the eighth segment. Tube fragile, 

 covered with sand-grains and minute stones. 



Synonyms. 

 1826. Terebella lutea, Risso. Hist. nat. TEurope merid., t. iv, p. 409. 



1828. Amjphitrite nesidensis, Delle Chiaje, Mem., vol. iii, pp. 169, 179, Tav. xliii, figs. 2, 3. 

 1841. „ „ idem. Descriz., vol. iii, p. 69, vol. v, p. 94, Tav. cv, figs. 2, 3. 



1843-53. Terebella „ Chenu. Illnst. Conch., ll e livr., pi. v, fig. 4. 



1848. Terebella lutea, Grrube. Arcliiv f. Naturg., xiv, p. 114, Taf. iv, figs. 9, 10. 

 1851. „ nesidensis, idem. Fam. AnneL, p. 81. 



1855. „ lutea, idem. Arch. f. Naturges., Bd. xxi, p. 116. 



1861. „ „ idem. Ausflug. Triest., pp. 85, 128. 



1864. „ „ idem. Insel. Lussin., p. 87. 



1865. „ Danielsseni, Malmgren. Nord. Hafs.-AnnuL, p. 379, Tab. xxi, fig. 54. 

 „ „ abbreviata, Ue Quatrefages. AmieL, t. ii, p. 363. 



„ „ nesidensis, idem. Ibid., p. 365. 



1867. Polymnia Danielsseni, Malmgren. Annul. Polych., p. 108. 



1868. Terebella flavescens, Claparede. Anne]. Nap., p. 396, pi. xxiii, fig. 6. 



1869. „ Danielsseni, Grube. Abhandl. Schles. (resell., 1868—9, p. 105. 



1870. „ abbreviata, idem. Arch. f. Naturges, 36 Jr., p. 334. 



1 Fifteen ventral scutes, the first eight being- short and wide, and the last triangular (Lo 

 Bianco) . 



