MAR´GO, _n._ Margin. _Margo mentalis_, inner boundary of the forks of
the mandible. _Margo malaris_, boundary of the base of the mala.
MARSU´PIUM, _n._ Vascular, erectile, membranous organ in the back
chamber of the eye of birds, supposed to aid in accommodation of vision.
Also called _pecten_.
MASSE´TER, _n._ One of the muscles that effect mastication.
MAS´TAX, _n._ “Side of the forepart of head, adjacent to the base of the
bill.” (37.) (Little used, and undistinguished from _lore_.)
MAS´TOID, _a._ Name of a process of the temporal bone.
MA´TRIX, _n._ Mould. Tissue or organ containing something and
determining its form or other condition.
MAXIL´LA, _n._ Jaw, especially the upper jaw, or _maxilla superior_; the
_maxilla inferior_ being especially called _mandibula_. (10.)
MAX´ILLAR, MAX´ILLARY, _a._ Pertaining to the upper jaw. _Maxillary
bone_, the cheek-bone; in birds an inconsiderable bone of the bill
itself, not of the cheek.
MAX´ILLO-PAL´ATINE (_bone_), _n._ Certain paired bone of the upper jaw
in the palate.
MEA´TUS, _n._ Passage or canal. _Meatus auditorius_, ear-passage.
ME´DIAN, _a._ Lying in the middle line. Opposed to _lateral_.
MEDIASTI´NUM, _n._ One of the thoracic partitions.
MEDUL´LA, _n._ Marrow. _Medulla spinalis_, spinal cord. _Medulla
oblongata_, tract of nerve matter between cerebellum and spinal cord
proper.
MEL´ANISM, _n._ State of coloration resulting from excess of black or
dark pigment; a frequent condition of hawks.
MELANIS´TIC, MELANOT´IC, _a._ Affected with melanism.
MEM´BRANA PUTAM´INIS, _n._ The lining membrane of the egg-shell, formed
of dense modified albumen.
MEM´BRANE, _n._ Thin soft sheet of various structure covering a part
or organ. _Cerebral_ or _spinal membrane_. See MENINGES. _Nictitating
membrane_, the third or inner eyelid of birds, which sweeps across the
ball. Soft skinny covering of the bill of many birds is said to be
_membranous_. Webbing of the toes is the interdigital _membrane_. _Loma_
is a fringed _membrane_.
MEM´BRUM, _n._; pl. _membra_. Any limb, or other peripheral part, as a
bill, as distinguished from body proper or _truncus_.
MENIN´GES, _n._ _pl._ Envelopes of the brain or spinal cord; especially
the _dura mater_ and _pia mater_. (The singular, _meninx_, is scarcely
used.)
MEN´TAL, _a._ Pertaining to the chin.
MEN´TUM, _n._ Chin; soft parts between the branches of the lower jaw.
MESENCEPH´ALON, _n._ A certain brain-tract, the second from behind.
MESENTER´IC, _a._ Pertaining to the mesentery.
MES´ENTERY, _n._ A fold of the peritoneum binding the intestines in
place.
MESERA´IC, _a._ Same as MESENTERIC (which see).
ME´SIAL, _a._ In the middle; same as _median_.
MESO- (_in composition_). Middle; median.
MESOMET´RIUM, _n._ Partially muscular peritoneal fold supporting the
oviduct.