SEDENTARI^. 137 



composed of grains of sand and fragnaents of shells, with cup- 

 shaped orifices. 



Sahellaria crassissima — The Thickest Sabellarta. Plate 

 XIX. fig. 22. Tubes long, thick, somewhat parallel, and con- 

 tiguous ; the openings nearly obsolete. 



Gem<s9.— PECTINARIA Lamarck. 



Generic Character. — Body tubicular, subcylindrical, attenua- 

 ted behind, with a row of setaceous papillae on either side; 

 bristles short, fasciculated ; broad, blunt, and oblique in front, 

 with golden yellow very brilliant transverse spangles; mouth 

 elongated, with two lips, surrounded with numerous short ten- 

 tacula; four pectinated exterior branchiae, placed on the second 

 and third segments of the body. Tube the shape of a reversed 

 cone, membranaceous or papyraceous ; consisting of sandy par- 

 ticles, and not adherent. 



Pectinaria Belgica. — The Belgic Pectinaria. Plate XIX. 

 fig. 23. Tube inversely conical, membranaceous and covered 

 with particles of sand. Inhabits the European seas. 



TRIBE III. MALDANIiE. 



With intermediate branchiee ; tube open at both ends. 



Genus 10.— DENTALI UM.— ZiVm««*. 



Generic Character. — Body tubicular, conical, with the an- 

 terior extremity exsertile and surrounded by a membranous ring ; 

 mouth terminal and naked. Tube testaceous, nearly regular, 

 slightly bent, attenuated towards the posterior extremity, and 

 open at both ends. 



* Tubes having longitudinal ribs or striae. 



Dentalium elephantinum. — The Elephantine Dentalium. 

 Plate XIX, fig. 27. Green, slightly bent, with ten longitudi- 

 nal ribs. Three or four inches long. Inhabits the Indian and 

 European seas. 



o 



