BORER or PIERCER. A term applied to those species of Acephalopodous Mollusca, which bore holes as dwellings in the rocks, as the Pholades, and some others. BRACHIOPODA. Lam. A family of symmetrical bivalves belonging to the third section of Lamarck's _order_ "Conchifera Monomyaria," described as bivalve (generally symmetrical) adhering to marine bodies, by a tendon passing through the shell, having no true ligament. What most distinguishes this family and renders it remarkable is the structure of the animal. It has two elongated, tendril-shaped arms. When the animal is in a state of repose these arms are coiled up spirally and enclosed in the shell, but when required for use, are unfolded and extended. This family contains the genera Orbicula, Terebratula and Lingula, in the system of Lamarck, to which may be added Thecidium, Productus, Spirifer, Magas, Pentamerus, Crania, Strigocephalus, Strophomena, and some others enumerated in the explanation of figures 201 to 219. The above genera may be thus distinguished. 1. ORBICULA. Umbones central; byssus passing through a hole in the flat valve. Fig. 201. 2. ATRYPA. Without foramen or space between the valves. Fig. 203. 3. PRODUCTA. The same, valves produced, overwrapping; including Leptæna. Fig. 206, 206*. 4. TEREBRATULA. Hinge of the upper valve produced beyond that of the other, with a pit or foramen; including _Delthyris_, _Orthis_, _Trigonosemus_, _Magas_, _Strophomena_. Fig. 202, 205, 207, 208, 209. 5. SPIRIFER. The same, with deep triangular area; spiral folds in the interior; including _Trigonotreta_ and _Cyrtia_. Fig. 204, 214, 215. 6. THECIDIUM. Large valve attached; curved ridges in the inner surface; two jutting points or teeth on the hinge. Fig. 216. 7. CRANIA. Attached by the surface of the valve; muscular impressions four, forming a face. Fig. 197, _a_, b. 8. PYCNODONTA. Irregular; hinge with raised pointed teeth. Fig. 217, 218. 9. PENTAMERUS. Valves divided by septa; including _Gypidia_. Fig. 210 to 213. 10. LINGULA. Valves equal, gaping, with a peduncle. Fig. 219. BRACHITOMA. Swainson. A genus composed of PLEUROTOMA strombiformis and similar species, described as "sub-fusiform; resembling a small Strombus or Fusus; spire and aperture of equal length; canal short; outer lip slightly ascending, and forming a short canal; sinus very small and nearly semicircular; inner lip thickened above. B. Strombiformis, Sow. Man. fig. 381." Europe, East and West Indies, China, &c. BRANCHIFERA. Bl. The second family of the order Cervicobranchiata, containing the following genera of symmetrical univalves:--Fissurella, Emarginula, and Parmophorus.