356 OWENIA FUSIFORMIS. 



anus, sometimes bilobed. Segments variable in length, the anterior region of three 

 segments bearing only bristles, the posterior bearing both bristles and hooks. A broad belt 

 of modified hypoderm stretches backward from the collar on each side in the dorso-lateral 

 region. Slender capillary bristles with spikes tapering distally. Hooks minute and very 

 numerous, with bifid tips. Larva a Mitraria. 



1. Owenia fusiform i s, Delle Ghiaje, 1842. Plate- XCII, fig. 6; Plate CI, figs. 8—8/— 

 tube, branchias, etc. ; Plate CX, figs. 9— 9b— bristle and hook. 



Specific Characters. — Cephalic region truncated, having dorsally a rounded elevation, 

 the longer diameter of which is transverse ; laterally two lobes sometimes marked by an 

 oblique groove slanting from above downward and iuward, and having the mouth at 

 their anterior border. A bilobed process with a tongue-shaped ventral appendage 

 projects below the mouth. Cephalic rim has three pairs of dichotomously divided 

 branchiae, the distal divisions being short, glandular, and truncated. They are semi- 

 transparent, greenish-blue or yellow, and tinted with red; those from Naples being 

 blood-red and pigmented with brown. A collar around the branchiae. Body 30 to 60 

 mm. in length, firm and rounded anteriorly, tapered posteriorly, where it ends in a 

 papillose anus — sometimes bilobed. Segments twenty-three to thirty in number, and 

 they vary much in. antero-posterior diameter, whilst the body is divided into an anterior 

 and a posterior region. The anterior region consists of three segments bearing only 

 dorsal bristles ; the posterior region has from seventeen to twenty-five segments, bearing 

 both dorsal bristles and tori for hooks ventrally. The first three segments are long, 

 whilst the eighth bristled segment inaugurates a change, for it has no dorsal glandular 

 bands, though it has hooks and bristles. Bristles of one type, viz. slender, tapering forms 

 with spikes directed distally. The tori bear a vast number of minute hooks, the neck 

 having a forward bulge below the tip, and then a shoulder below, after which the long 

 shaft tapers gradually to a long, slender thread. Hooks minute, bifid at the tip and 

 with a prominent convexity posteriorly. Tube with a thick internal lining of secretion 

 which forms two conical, elastic, and membranous ends, whilst the general surface is 

 densely covered with imbricated fragments of shells. 



Synonyms. 



1842. Owenia fusif or mis, Delle Chiaje. Descriz., pi. 175, figs. 1 — 6. 



1846. Ammochares ottonis, Grube. Arch. f. Naturges., Bd. xii, p. 163, pi. v, fig. 2. 



1851. ,, , ; idem. Fam. Annel., pp. 77 and 137. 



„ ,, assimilis, Sars. Nyt Mag. f. Naturvid., Bd. vi, p. 201. 



1853. „ ,, idem. Ibid., Bd. vii, p. 390. 



1861. „ „ Danielssen. Ibid., Bd. xi, p. 54. 



1864. ,, ottonis, Kolliker. Kurzer Bericht, p. 10. 



., „ „ idem. Wurzb. Naturw. Zeitschr., Bd. v, p. 241. 



1865. Ops digitata, Carrington. Ann el. Sonthport, p. 11. 



,, Ammochares ottonis, De Quatrefages. Anneh, t. ii, p. 249. 

 1867. „ assimilis, Malmgren. Annul. Polycheet., p. 101, Taf. 11, fig. 65. 



