Of another British tube builder which builds tubes of cemented shells or pebbles near the roots of large sea weeds, Rev. Richard Johnston says: “Sabellarid angilica is a timid, lively, active creature whose most prominent ability is that of constructing a dwelling for itself from sand grains. It is firm, durable, and capable of great resistance. They are not easily crushed. Some appear much more brittle. Most of the dwellings are lined with a soft, silky substance formed of exudations from the body. The worms have a great preference in building materials. They always prefer sand or shells. Powdered glass is used reluctantly and soon rejected. Some tubes are short and confined, others considerably prolonged so as to afford safe retreats in danger. Some architects seem to persist in prolonging the fabric as long as material can be found. They never weary of working. Grains of sand are selected and adopted for precise spots and gelatinous matter secures them in the tube walls.” Perhaps the most notable of all the worm builders is a five-inch-long species found in South African waters, pectinaris capensis, described by Sir John McIntosh: “The beautiful straight tube formed by this animal was composed of the spicules of sponges in short lengths placed traversely and fixed by secretion so as to form a perfectly round tunnel gently tapered from the wide to the narrow end. The spicules appeared of the same size throughout the tube. The inner surface was as smoothly formed as the outer. The labor involved in selecting and fitting with such marvelous skill the sponge spicules composing so large a tube must have been very arduous. One tube lasts the animal for life.” McIntosh tells of another South African architect worm that “builds out of grains of sand arranged in a single layer like miniature masonry and bound together by waterproof cement.” There are, however, widely differing degrees of artistry among the tube-dwelling polychaetes. Some tubes are rough, fragile, long, bent in various directions, and united in colonies several inches to a foot across. Sometimes tubes three to four inches long are attached horizontally to the undersides of rocks. A large and singular terebellid is Amphitrite ornata—twelve to fifteen inches long with orange-brown tentacles capable of being extended eight to ten inches. These are kept in constant motion gathering food and material for building. The bodies of these worms are filled with blood, but there is no circulatory system. The blood, however, apparently can be forced into any part of the body by muscular contractions. The tentacles can be turned voluntarily in any direction by forcing blood into them. Tube-building, flowering worms excited the wonder of Quatrefages as he observed them along the Bay of Biscay in the nineteenth century: