1 56 SEDENTARIJE. 



attenuated behind, with many annulated segments ; and a single 

 row of setiferous papiiise^bristles subulate, fasciculate and hooked 

 setce ; branchiae in slender finger-shaped fasciculi, disposed like 

 a fan, and spreading into a disk ; two short subulate filaments 

 inserted at the internal base of the branchiae, between which is 

 a terminal mouth ; tube elongated, cylindrical, tapering towards 

 the base, membranous or coriaceous and generally naked. 



Amphitrile ventilahrum. — The Fan Amphitrite. Plate 

 XIX. fig. 19. Tube tapering, incurved, and smooth ; of a 

 cream yellow colour. Inhabits the Mediterranean sea. 



Genus 7.— TEREBELLA.— ZawarcA. 



Generic Character. — Body tubicular, elongated, cylindrically 

 depressed, attenuated posteriorly, segments transverse, and sub- 

 annulated ; having a row of nodulous and setiferous papillae on 

 each side ; with numerous filiform, twisted tentacula surround- 

 ing the mouth, and terminating in front of it ; two rows ot 

 ramose branchiae placed in a single row beneath the tentacula ; 

 tube elongated, cylindrical, attenuated and pointed at the base, 

 membranous, consisting of agglutinated grains of sand and frag- 

 ments of shells. 



Terebella conchilega. — The Shelly Terebella. Plate 

 XIX. fig. 21. Tube covered %vith numerous fragments of 

 broken shells agglutinated together ; with three branchiae on 

 each side. Inhabits the coasts of Holland. 



** With short branchias ; tentacula short or awanting. 



Genus 8. — SABELL ARIA.— Xa/narcA. 



Generic Character. — Body tubicular, subcylindrical, attenua- 

 ted behind ; with fasciculi of subulate bristles in a single row on 

 each side, and spatulous bristles and transverse laminae, armed 

 with hooked setce; anterior extremity obliquely truncated, ellip- 

 tical, surmounted by six rows of brilliant spangles, three rows 

 on either side ; mouth elongated, cleft, with two lips, the 

 under one short and internal ; with small branchiae placed near 

 the mouth ; tubes numerous, congregated in a common mass, 



