POLYCH^Ta 293 



1. Spio Fabiicins. Segments alike throughout; head with a promi- 

 nent median lobe which may be truncated or divided in front; 4 eyes; 

 gills on all the segments: several species, 2 at Woods Hole. 



S. setosa Verrill (Fig. 467). Body long, flattened above and rounded 

 below; parapodia 2-lobed; color green; gills and cirri red; length 8 cm.; 

 width 2.5 mm. : Lfong Island and Vineyard Sounds; at low- 

 water mark. 



2. Laonice Malmgren. Segments alike throughout; 

 prostomium with 2 or 4 eyes, very broad in front; gills 

 absent from hinder half at least of body : several species, 

 2 at Woods Hole. -^ig. 467 



L. {Scolecolepis Blainville) viridis (Verrill). Body ^fiJiV^fcToT 



flattened; color olive green or brownish; length 10 cm.; ^^verrfiiT*^ 



breadth 3 mm.: Long Island and Vineyard Sounds; near ^' ^cir^i^'s"''^^ 

 low-water mark; often common. 



3. PoLYDORA Bosc. Fifth segment different from the others, being 

 much longer and with characteristic setae: many species, 7 at Woods 

 Hole. 



P. concharum Verrill. Body long and slender, being 14 cm. long 

 and 1.5 mm. wide, with 200 segments; color grayish or yellowish: very 

 common from Cape Cod to Nova Scotia; in 10 to 100 fathoms, often 

 burrowing in shells. 



Family 2. CH^TOPTEEIDAK 



Worms living in U-shaped parchment-like tubes up to 50 cm. long, 

 buried in the sand and mud; 3 distinct regions in the body; no tentacles 

 or palps present and but 1 pair of peristomial cirri which tend to project 

 backwards; proboscis w^anting: few genera and species. 



Ch^etopteeus Cuvier. Parapodia simple, consisting of large, ex- 

 panded notopodia in the anterior body region, but may be biramous in 

 the other two regions: 15 species, 1 at Woods Hole. 



C. pergamentaceus Cuv. Body short and stout; anterior region 

 much flattened; middle region composed of 1 segment with large wing- 

 like parapodia and 4 swollen segments; body walls very thin, intestine 

 and genital products showing through; highly phosphorescent; length 

 15 cti. : North Carolina to Cape Cod; Europe. 



Suborder 3. TEREBELLIFORMIA. 



Prostomium a prominent lobe with or without tentaculai'^iilftments 

 which represent the tentacles and without palps; peristomium witfe\pr 

 without cirri; parapodia weak, without ventral cirri, the dorsal ciri*i-. 



