5. AMPHIDESMA. A distinct external ligament, internal ligament oblique. Fig. 85. 6. ERYCINA. A short tooth on each side of the cartilaginous pit in each valve. Including Mesodesma. Fig. 86. 7. UNGULINA. Ligament flat, divided. Fig. 88. MACULATED. (From _Macula_, a spot.) Spotted or patched. This term is applied by conchological writers, to those shells which are coloured in spots or small patches. In the same sense it is also used as a specific name. As for instance, Cytherea maculata, fig. 167, c. and Hippopus maculatus, fig. 156. MAGAS. Sow. ([Greek: Magas], _magas_, a board, a deck.) _Fam._ Brachiopoda, Lam.--_Descr._ Equilateral, inequivalve; one valve convex, with a triangular area, divided by an angular sinus in the centre; the other valve flat, with a straight hinge line and two small projections; a partial longitudinal septum, with appendages attached to the hinge within. Differing from Terebratula in having a triangular disc, and not a circular perforation. Magas pumilus, fig. 299. Fossil in chalk. MAGILUS. Montf. _Fam._ Cricostomata, Bl. Serpulacea, Lam.--_Descr._ Thick, tubular, irregular, contorted; rounded above, keeled beneath, free; apicial extremity convolute, heliciform, ovate or sub-globose; aperture elliptical.--_Obs._ This shell when in a young state presents the characteristics of a regularly formed spiral univalve, living in holes in madrepores. As the madrepore increases in bulk, the animal gives an eccentric course to the shell, in order to have its aperture even with the surface, and leaving the nucleus or young shell behind, fills it up with calcareous matter to reside in the open extremity of the tube. Fig. 9, 10. Red Sea and Mauritius. MALACOTA. Schum. OTION. Leach. MALACOZOA. Bl. ([Greek: Malakos], _malacos_, soft; [Greek: Zôon], _zoon_, animal.) The type or general appellative in De Blainville's system, including all molluscous animals, excepting those with multivalve shells. MALDANIA. Lam. The second family of the order Annelides Sedentaria. The only genus of shells described in this family is Dentalium, fig. 2, to which may be added Pharetrium, König. fig. 3. It is doubtful however whether the latter do not belong to an unknown genus of Pteropodous Mollusca. MALEA. Valenciennes. A genus composed of DOLIUM latilabrum, Kiener, and other similar species. MALENTOZOA. Bl. ([Greek: Malakos], _malacos_, soft; [Greek: en], _in_, [Greek: temnô], _temno_, cut; [Greek: Zôon], _zoon_, animal.) Or articulated mollusca. The sub-type in De Blainville's system, comprehending those with multivalve shells. MALLEACEA. Lam. A family belonging to the order of Conchifera Monomyaria. Containing the following genera of irregular pearly bivalves.