POLYCHAETE WORMS, PART 1 57 



Genus Hipponoe Aiidouin ajid Milne-Edwards, 1830 



Metamphinome Treadwell, 1940; type (monotypy) : Metamphinome muUihranchiala 

 Treadwell, 1940; =//. gaudichaudi Audouin and Milne-Edwards, 1830. 



Type (monotyp}'): Hijjponoe gaudichavdi Audouin and Milne- 

 Edwards, 1830. Contains only one New England species. 



Hipponoe gaiidicJiandi Audouin and Milne-Edwards, 1830 



Figure 13,a,6 



Hipponoe gaudichaudi Moore, 1903b, p. 793. — Willey, 1910, p. 180.— Sumner, 

 Osburn, and Cole, 1913, p. 619.— Augener, 1922, p. 39.— Fauvel, 1923, p. 132, 

 fig. 47,Z-p; 1936b, p. 19.— St0p-Bowitz, 1948a, p. 15.— Okuda, 1950, p. 49, 

 figs. a-b. — Fauvel and Rullier, 1959, p. 510. 



Hipponoe midtibranchiata Ilartman, 1951, p. 29, pi. 8, figs. 1-2. 



Description. — Length up to 42 mm., width up to 10 mm., seg- 

 ments 25-32. Prostomium small, suboval, with 4 subequal eyes ar- 

 ranged in rectangle (rarely missing?), with 5 filiform appendages — 

 subequal paired lateral antennae and lateral palps; median antenna 

 longer (fig. 13a). Without prostomial caruncle. Branchiae arbores- 

 cent, richly branched, beginning on setiger 3 and continuing pos- 

 teriorly. Dorsal cirri digitiform, nearly as long as notosetae. Ventral 

 cirri reduced to short cushions ventral to neurosetae. Notopodia 

 dorsolateral in position, with fan-shaped bundle of slender, fine noto- 

 setae (fig. 13a). Neuropodia ventral in position about midway be- 

 tween midventral line and lateral side, with circular rim within which 

 are a gi'oup of short, stout, bifid hooked neurosetae (with long terminal 

 hook and shorter one beneath, fig. 136). Color, in life: deep orange 

 to vermilion red. 



Biology. — Floating objects apparently the normal habitat of the 

 species. Found clinging to logs or floating objects bearing masses 

 of goose or stalked barnacles (as Lepas anatifera Linne, L. fascicularis 

 Ellis and Solander, L.f. aurivillii Nilsson-Cantell, L. pectinata Spengle, 

 L. ansifera Linne) upon which they feed. Accordhig to Moore (1903b), 

 they are found on the under side of logs away from the light, asso- 

 ciated with crabs and nudibranchs, and less frequently on the sides 

 and upper surfaces of barnacles. Oing most tenaciously by means of 

 tlieir strong neuropodial hooks and move very sluggishly. Found 

 within the valves of Lepas. Okuda (1950) recorded a female distended 

 with ova, living commensally within the branchial chamber of Lepas. 

 Sexually mature individuals taken in the summer in the Woods Hole 

 area (Sumner, 1913). They have a rich uniform pinkish coloration 

 resembling the color of tlie egg ribbons of the L^epas (Willey, 1910). 

 Young remain attached to the lateral and ventral sides of the fenuxle — 

 at one time considered to be parasites (Augener, 1922). Specimens 



