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 exogenous wood, which pass from the pith to the bark.Medullary sheath(Anat.), the layer of white semifluid substance between the primitive sheath and axis cylinder of a medullated nerve fiber.

(Me*dul"la*ted) a. (Anat.) Furnished with a medulla or marrow, or with a medullary sheath; as, a medullated nerve fiber.

(Me*dul"lin) n. [Cf. F. médulline.] (Bot. Chem.) A variety of lignin or cellulose found in the medulla, or pith, of certain plants. Cf. Lignin, and Cellulose.

(||Me*du"sa) n. [L., fr. Gr. .]

1. (Class. Myth.) The Gorgon; or one of the Gorgons whose hair was changed into serpents, after which all who looked upon her were turned into stone.

2. [pl. Medusae ] (Zoöl.) Any free swimming acaleph; a jellyfish.

The larger medusæ belong to the Discophora, and are sometimes called covered-eyed medusæ; others, known as naked-eyed medusæ, belong to the Hydroidea, and are usually developed by budding from hydroids. See Discophora, Hydroidea, and Hydromedusa.

Medusa bud(Zoöl.), one of the buds of a hydroid, destined to develop into a gonophore or medusa. See Athecata, and Gonotheca.Medusa's head. (a) (Zoöl.) An astrophyton. (b) (Astron.) A cluster of stars in the constellation Perseus. It contains the bright star Algol.

(Me*du"si*an) n. (Zoöl.) A medusa.

(Me*du"si*form) a. [Medusa + -form.] (Zoöl.) Resembling a medusa in shape or structure.

(Me*du"soid) a. [Medusa + -oid.] (Zoöl.) Like a medusa; having the fundamental structure of a medusa, but without a locomotive disk; — said of the sessile gonophores of hydroids.n. A sessile gonophore. See Illust. under Gonosome.

(Meech) v. i. See Mich. [Obs. or Colloq.]

(Meed) n. [OE. mede, AS. med, meord; akin to OS. meda, OHG. miata, mieta, G. miethe hire, Goth. mizdo reward, Bohem. & Russ. mzda, Gr. mistho`s, Skr. midha. &radic276.]

1. That which is bestowed or rendered in consideration of merit; reward; recompense.

A rosy garland was the victor's meed.

cranial nerves arise. It controls very largely respiration, circulation, swallowing, and other functions, and is the most vital part of the brain; — called also bulb of the spinal cord. See Brain.

(Me*dul"lar) a. See Medullary.

(Med"ul*la*ry) a. [L. medullaris, fr. medulla marrow: cf. F. médullaire.]

1. (Anat.) (a) Pertaining to, consisting of, or resembling, marrow or medulla. (b) Pertaining to the medula oblongata.

2. (Bot.) Filled with spongy pith; pithy.

  By PanEris using Melati.

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