172 SPIO FILICORNIS. 



The dorsal bristles (Plate CVI, fig. 10), after the fifteenth bristled segment, soon 

 greatly increase in length, the npper especially being long and hair-like, and they become 

 gradually longer in their progress backward, till near the tail, where they are shorter. 

 The dorsal lamellae throughout the posterior region are small, conical papillae, which 

 lie behind the setigerous process. The ventral lamella posteriorly is represented only by 

 the papilla for the hooks. 



So far as can be observed this form differs from the two species described by 

 0. Fabricius, but approaches an imperfect example of Prionospio. 



3. Spio filioornis, 0. Fabricius, 1789 (?). Plate XCVIII, figs. 11 and 11 a— head and 

 first foot; Plate XCVII, figs. 9-9 c— feet; Plate OV, fig. 13— hook. 



Specific Characters. — Head terminating anteriorly in a rounded point — the centre of a 

 cone formed by the buccal segment. A minute black eye on each side of the median 

 ridge, which ends in an occipital papilla or tentacle posteriorly. Body about an inch in 

 length, proportionally short and stout, a little tapered anteriorly and more so posteriorly, 

 where it ends in two broadly ovate cirri. Branchiae conspicuous from the first foot to the 

 end. Dorsal lamella of first foot elongate-ovoid, with about one-third of dorsal edge free, 

 the rest fused to the base of the branchia, the lower margin trending gently to the body- 

 wall. Dorsal bristles of moderate length, curved upward and slightly backward, finely 

 tapered, the upper series longest and most slender. Ventral lamella is a prominent, 

 obtusely ovate, process. By-and-by the superior lamella is flattened externally and less 

 free superiorly, and the ventral lamella assumes a rhomboidal outline, rounded at the 

 inferior angle. Winged hooks, with a main fang and a spike on the crown, commence in 

 the ventral division about the thirteenth foot, along with the delicate bristles. The 

 lamellae increase in size before the fiftieth foot, the winged hooks, to the number of nine, 

 occupying nearly the entire length of the ventral lamella. 



Synonyms. 

 1776. Nereis filicornis, 0. F. Midler. Zool. Danica Prod., p. 218, No. 2640. 

 „ 0. Fabricius. Fauna Greenland., p. 307, No. 289. 



„ idem. Schrift. Naturf. Freunde Berlin, Bd. vi, p. 264, Tab. v, figs. 8—12. 



„ Grmelin. Linn. Syst. Nat., ed. 13, i, p. 3110. 



„ Lamarck. Hist. Anim. sans Vert., t. v, p. 319, No. 2. 



,, Savigny. Syst. Annel., p, 45. 



„ De Blainville. Diet. Sc. nat., t. lvii, p. 441. 



„ „ „ Delle Chiaje. Mem., p. 176. 



1843. „ „ (Ersted. Grcenl. Annul. Dorsibr., p. 203. 

 „ „ „ idem. Annul. Danic. Consp., p. 40. 



1844. „ „ idem. Reg. Mar., p. 68. 



„ „ „ idem. Arch. f. Naturges., Bd. x, p. 106. 



1851. „ „ Grube. Fam. Annel., pp. 66 and 134. 



„ „ „ Maitland. Fauna Belg., p. 210. 



1867. „ „ Malmgren. Annul. Polych., p. 91, Tab. i, figs. 1— Id 3 . 



1879. „ „ Tauber. Annul. Danica, p. 117. 



„ „ „ Theel. Kongl. svenska Vet.-Akad. Handl., Bd. xvi, p. 54. 



1785. 



Spio 



1791. 



» 



1818. 



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1820. 



)> 



1828. 



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