Pectinaria Belgica. Pectinaria capensis. _P. Belgica._ The Belgic Pectinaria. Tube inversely conic, membranous, and covered with sand. 2. Sabellaria. Two species. The covering of the animal belonging to this genus is composed of fragments and particles of marine substances, adhering to a tubular membrane; some are detached and others are fixed. The tubes are cellular at the base, and the orifice expanded. Sabellaria alveolata. Sabellaria crassissima. _S. alveolata._ The Honeycomb Sabellaria. Consists of numerous parallel tubes, nearly straight, communicating by an aperture, forming when in mass the appearance of a honeycomb; it adheres to rocks in clusters. _S. crassissima._ The very thick or strong Sabellaria. Pl. 33, fig. 2. Species incrusted with small stones; sometimes found thick and of a large size. 3. Terebella. Three species. Tube elongated, cylindrical, membranous, attenuated and pointed at the base, with adhesions of sand. Terebella conchilega. T. cristata. T. ventricosa. _T. conchilega._ The shelly Terebella. Tube covered with numerous fragments of broken shells. 4. Amphitrite. Six species. Nearly the same as the Terebella, but of a tougher membranous texture, and generally without adhesions. Amphitrite ventilabrum. A. penicillus. A. magnifica. A. vesiculosa. A. volutacornis. A. infundibulum. _A. ventilabrum._ The Fan Amphitrite. Tube subulate, smooth, of a yellowish colour. FAMILY IV. SERPULACEA. Five genera. 1. Spirorbis. Five species. Tube testaceous, spirally twisted on a horizontal plane, with terminal aperture rounded or angular, attached by the lower part to marine substances. Spirorbis Nautiloides. S. spirillum. S. carinata. S. lamellosa. S. tricostalis. _S. Nautiloides._ The Nautilus-shaped Spirorbis. White, transversely wrinkled and minute. 2. Serpula. The Worm Shell. Twenty-six species. The name of this genus is derived from the Latin word serpo, to creep, on account of the vermiform character of some of its species. They are invariably tubular, sometimes solitary, but more frequently in clusters spirally entwined, adhering to marine substances. In colour they are brown, purple, yellow, tawny, pink or white, and sometimes tinged with green. Tube solid, calcareous, irregularly twisted, fixed to other substances.