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See Medullary.

Filled with spongy pith; pithy. Medullary groove (Anat.), a groove, in the epiblast of the vertebrate blastoderm, the edges of which unite, making a tube (the medullary canal) from which the brain and spinal cord are developed. -- Medullary rays (Bot.), the rays of cellular tissue seen in a transverse section of exoge…

The layer of vascular connective tissue lining the medullary cavities of bone.

grain of timber which is transverse to the annular rings or plates; the direction of the medullary rays in oak and some other timber. Knight.

The marrow of bones; the deep or inner portion of an organ or part; as, the medulla, or medullary substance, of the kidney; specifically, the medula oblongata.

Furnished with a medulla or marrow, or with a medullary sheath; as, a medullated nerve fiber.

A soft white substance constituting the medullary sheats of nerve fibers, and composed mainly of cholesterin, lecithin, cerebrin, albumin, and some fat.

ithelium cells, and resembling, if not identical with, the substance (myelin) forming the medullary sheaths of nerve fibers.

e enteron; as, the neurenteric canal, which, in embroys of many vertebrates, connects the medullary tube and the primitive intestine. See Illust. of Ectoderm.

Not medullated; (Anat.) without a medulla or marrow, or without a medullary sheath; as, a nonmedullated nerve fiber.

An elastic cartilagelike rod which is developed beneath the medullary groove in the vertebrate embryo, and constitutes the primitive axial skeleton around which the centra of the vertebræ and the posterior part of the base of the skull are developed; the chorda dorsalis. See Illust. of Ectoderm.

nd live many centuries. The wood is usually hard and tough, and provided with conspicuous medullary rays, forming the silver grain.

Of or pertaining to the medulla oblongata; medullar.

epression or groove in the epiblast of the primitive streak. It is not connected with the medullary groove, which appears later and in front of it. -- Primitive plane (Spherical Projection), the plane upon which the projections are made, generally coinciding with some principal circle of the sphere, as the equator or…

The substance of the medullary sheath.

plates of cellular tissue which pass from the pith to the bark of an exogenous stem; the medullary rays. In the wood of the oak they are much larger than in that of the beech, maple, pine, cherry, etc. -- Silver grebe (Zoöl.), the red-throated diver. See Illust. under Diver. -- Silver hake (Zoöl.), the American whit…