)30 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 15 



Paraonis gracilis (Tauber) 1879 

 Plate 44, figs. 4, 5 



Aonides gracilis Tauber, 1879, p. 115. 



Levinsenia gracilis Mesnil and Caullery, 1898, p. 136-137, pi. 6, fig. 10. 

 Paraonis {Paraonis) gracilis Cerruti, 1909, pp. 468, 498, 504. 

 Paraonis gracilis Eliason, 1920, pp. 55-56, fig. 16 a-e; Wesenberg-Lund, 

 1950b, p. 32, fig. 34; Wesenberg-Lund, 1953, p. 59-60; South- 

 ward, 1955, p. 264. 

 IParaonis (Paraonides) gracilis Monro, 1930, pp. 150-152, fig. 58. 

 Aonides gracilis Day, 1934, p. 60. 

 Paraonis filiformis Hartman, 1953, pp. 39-40, fig. 12 b, c. 



Collection. — Long Island Sound, New York, from soft bottoms in 

 shallow water (4, collected by Howard Sanders in 1954). 



Individuals from Long Island Sound are uniformly slender and 

 immature. They measure at most about 20 mm long and 0.15 to 0.2 

 mm wide. The body is moniliform in the branchial region and cylindri- 

 cal farther back where segmental grooves are obscure, parapodia greatly 

 reduced and visible chiefly because of the projecting setal fascicles. The 

 longitudinal muscles are conspicuously visible through the body wall, 

 especially as seen in transmitted light. 



The prostomium is a depressed, long conical lobe with a palpode 

 (fig. 4) at its frontal margin; eyes are not visible. The first five segments 

 are prebranchial ; they have laterally directed setae in biramous arrange- 

 ment. The next 11 or 12 segments have large, simple, lingulate branchiae 

 directed upward; the middle ones are largest and longest; all are well 

 developed and fimbriated along their lateral margins. Parapodial lobes 

 are inconspicuous. The proboscis, everted in some individuals, is a large 

 globular sack exceeding the body in width. 



Setae in prebranchial and branchial segments are all long, slender 

 and distally pointed. In postbranchial segments the neuropodia have 

 series of curved or sigmoid hooks without a distal hood ; they number 

 one, two or three in a transverse row and are accompanied by one or 

 more capillary setae. The hooks have a thickened shoulder where the 

 seta emerges from the body wall. 



In individuals from western Europe the length is said to be 15 to 20 

 mm, width 0.5 to 0.8 mm, and segments number 50 to 100 (Eliason, 

 1920). Branchiae are present from the sixth or seventh segment and 

 number 12 to 14 pairs. Notopodia and neuropodia are inconspicuous. 

 Notopodial setae are all slender and hairlike. Anterior neuropodia have 



