MALLEUS. | 61 
impressions two, lateral; palleal impression with a small sinus. 
Obs. This genus contains many species of beautiful shells found 
in various parts of the world, some are common in Britain. 
Fossil species are not numerous, they occur in the tertiary strata. 
Fig. 79 to 82. 
MAC’TRADZE. Lam. A family of the order Conchifera Dimy- 
aria, Lam Sect. Tenuipedes, composed of equivalve shells, 
generally gaping, with ligament internal. This family contains 
the genera Lutraria, Mactra, Crassatella, Erycina, Ungulina, 
Solenimya, and other genera enumerated in explanation of 
figures 79 to 88. 
MA’GAS. Sow. (Mayas, magas, a board, a deck.) Ham. Brachio- 
poda, Lam. Descr. Equilateral, inequivalve ; one valve convex, 
with a triangular area, divided by an angular sinus in the cen- 
tre, the other valve flat, with a straight hinge line and two 
small projections; a partial longitudinal septum, with appen- 
dages attached to the hinge within. Differing from Terebra- 
tula in having a triangular disc, and not a circular perforation. 
Magas pumilus, fig. 209. 
MAGI’LUS. Montf. Fam. Cricostomata, Bl. Serpulacea, Lam. 
Descr. Thick, tubular, irregular contorted; rounded above, 
keeled beneath, free; apical 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 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, fills it up with calcareous 
matter, to reside in the open extremity of the tube. 
MALACO’TA. Schum. Orion, Leach. 
MAL’ACOZOA‘RIA. BI. (Manakos, malacos, soft; Zwov zoon, 
animal.) The type or general appellative in De Blainville’s 
system, including all molluscous animals, excepting those with 
multivalve shells. 
MALDA‘NIA. Lam. The second family of the order Annelides 
Sedentaria. The only genus of shells described in this family 
is Dentalium, fig. 2. 
MALEN’TOZOA’RIA. Bl. (Mandakos, malacos, soft; ev, in, reuveo, 
temno, to cut; Zor, zoon, animal.) Or articulated mollusca. 
Sub-type in De Blainville’s system, comprehending those with 
multivalve shells. 
MALLEA’CEA. Lam. A family belonging to the order Con- 
chifera Monomyaria, containing the genera Crenatula, Perna, 
Malleus, Avicula, Meleagrina; to which may be added other 
genera‘enumerated in explanation of fig. 163, to 170. 
MALULEUS. Lam. (Malleus,a hammer.) Fam. Malleacea, Lam. 
Margaritacea, Bl. Descr. Equivalve, inequilateral, foliaceous, 
trilobate, undulated, irregular, attached by a byssus passing 
