3. Genus Terebella. Pl. [V].

Animal. Body tubicular, elongated, cylindrically depressed, attenuated posteriorly; a row of nodulous and setiferous papillæ on each side; numerous filiform, twisted tentacula surrounding the mouth.

Shell. An elongated cylindrical and membranous tube with lash-like appendages at the end; covered with adhesions of sand and shells. Inhabits the coast of New Holland. Four species.

4. Genus Amphitrite. Pl. [V].

Animal. Body tubicular, elongated, cylindrical, attenuated behind with many annulated segments.

Shell. An elongated cylindrical tube growing thinner towards the base, of a tough membranous texture, and generally without adhesions. Mediterranean sea. Seven species.

FAMILY IV.
Serpulacea. Five Genera.