70 AMPHICTEIS GUNNER! 



Genus CXXXIX. — Amphicteis, Grube, 1860. (Amphitrite, Sars, 1835.) 



Shield-like cephalic lobe bounded by a prominent lobe (palp, Fauvel) on each side, 

 Which follows the shape of the shield posteriorly, median groove anteriorly. Nuchal 

 organs cushion-like. Tentacles smooth. Body enlarged anteriorly, tapering posteriorly. 

 Second segment (buccal) short, naked. Third segment large and prominent, with a 

 transverse division inferiorly, and bearing at each side the fascicle of palea3. Branchiae 

 subulate, four on each side, arising from the third, fourth, and fifth segments. Bristled 

 segments seventeen, commencing on the fourth (third, Hessle). Uncinigerous pinnules 

 begin on the seventh and extend to the segment in front of the anus. No distinct cirri 

 on the feet. Anal segment with two cirri. Capillary bristles with curved and tapered 

 tips arising from a subcylindrical base. Hooks commence on the sixth segment, uniserial, 

 subtriangular, rounded, five to six long teeth. Stomach with internal diverticula. No 

 ventral glands. Four to five pairs of similar nephridia, short and wide, the anterior 

 smaller than the posterior ; the apertures in the fourth segment do not open dorsally. 

 Diaphragm between the fourth and fifth segments and between the fifth and sixth. 

 Tube composed of mud. 



1. Amphioteis Gunneri, Sars, 1835. Plate CXVIII, fig. 7— body; Plate CXXIV, 



figs. 5 — 5 b ' — palea, bristles and hooks. 



Specific Characters. — Palmulse (eight to twenty) flattened, with a long tapering 

 apex. Tentacles about twenty, smooth. Body 30 mm. long, and 3 mm. across feet. 

 Segments 34 — 35, ventrally grooved. Branchiae filiform, four on each side, on third 

 and fourth segments. Posterior region with fifteen hook-laminae, and terminating 

 in two anal cirri. Feet with a clavate papilla at the ventral edge distally. Capillary 

 bristles with curved tips and wings striated at the base. Middle part of hook broadest, 

 with six teeth. Nephridia in fourth to seventh segments. Colour pale yellow, roseate 

 ventrally, with the brown stomach and greenish blood-vessels shining through. The 

 branchiae are greenish, annulated with brown, white and yellow. The first four segments 

 ventrally are marked with whitish and large brown touches. The dorsal surface has 

 whitish touches, and the cephalic lobe has brownish spots (Fauvel). Tube of mud with 

 fragments of algae and other sea-weeds. 



Synonyms. 



1835. Amphitrite Gunneri, Sars. Beskrivel., p. 50, Tab. xi, fig. 30. 

 1844 „ „ (Ersted. Nat. Tidsk., 2 ser., i, p. 415. 



„ „ „ idem. Kegion. Mar., p. 79. 



1851. Amphicteis ,, Grube. Fam. Annel., pp. 82 and 138. 

 1853. „ „ Sars. Nyt Mag., vii, p. 390, etc. 



1855. Crossostoma midas, Grosse. Ann. Nat. Hist., vol. xvi, p. 310, pi. viii, figs. 7 — 12. 



1857. Amphicteis Gunneri, Koren. Nyt Mag. f. Nat., ix, p. 94. 



1858. „ „ F. Miiller. Archiv f. Naturges., pp. 211— 220, 2 plates. 



1859. „ „ Danielssen. Kongl. Norsk. Vid. Selsk., p. 124. 



