POLYCH^TA 



291 



A. opalina (Verrill) (Fig. 464). Body cylindrical, largest in the 

 middle, reddish or yellowish in color, up to 40 cm. long, and 3 mm. wide : 

 North Carolina to Maine; burrowing in muddy sand; common; West 

 Indies. 



6. Stauronereis Verrill. Prostomium small and 

 quadrangular with 2 tentacles and 2 palps; gills not 

 present, the dorsal cirri being long and slender: several 

 species, 1 in the Woods Hole region. 



S. pallidus Veiv. Two pairs of eyes present; color 

 pale yellow; length 5 cm.; width .7 mm.: Virginia to Cape 

 Cod ; in the sand at low-w^ater mark. 



Family 



GLYCEEIDAE. 



Fig. 464 

 Arabella 

 opalina — 

 anterior end 

 (Verrill). 



Elongated cylindrical worms with usually small para- 

 podia, and an annulated prostomium which bears 4 small 

 tentacles and 2 rudimentary palps; proboscis very large and long, with 

 4 teeth; special retractile gills present either on the body wall or the 

 parapodia: about 5 genera; the worms live in cylindrical passages in the 

 sand, which they make with the proboscis. 



Key to the genera of Glyceridae here described : 



a-x Parapodia of same structure throughout 1. Glycera 



a2 Parapodia with 1 lobe on anterior third of body and 2 



lobes on posterior portions 2. Goniada 



1. Glycera Savigny. Parapodia of the same struc- 

 ture throughout: several species, 3 at Woods Hole. 



G. dibranchiata Ehlers (Fig. 465). Length 20 cm.; 

 prostomium sharp and conical; both dorsal and ventral 

 gills large, simple, and flat : from North 

 Carolina to Bay of Fundy and north- 

 wards; in shallow water, burrowing 

 very rapidly in sand and mud; often 

 very common. 



G. americana Leidy (Fig. 466). 

 Length 20 cm. ; width 4 mm. ; dorsal gills 

 branched; ventral gills absent: from 

 South Carolina to Cape Cod ; in shallow 

 water; not so common as G. dibrancJiiata. 



2. Goniada Audouin and Edwards. Parapodia on the first third 

 of the body with a single lobe, on hinder part with 2 lobes: several 

 species, 2 in New England. 



G. maculata Oersted. Body slender with about 194 segments; the 

 first 40 parapodia 1-lobed, the following 2-lobed; 2 principal teeth; 



Fig. 465 — Glycera 

 dihranchiata — an- 

 terior end (Verrill). 

 1, prostomium. 



Fig. 466 



Glycera 



americana — 



anterior end 



with proboscis 



extended 



(Verrill). 



