VESICLE

n. Ve2s'i2-k'l. Gr., KVTOS. Lat., vesicula (dim. of vested, a bladder). Fr., vesicule. Qer.,Bldschen, Blase. 1. A little sac or cyst; in histology, a minute solid or semisolid ma (e. g., a cell or nucleus) inclosed by a membrane. [J.] 2. A lesion of the skin or mucous membrane formed by a collection of clear liquid within or beneath the epithelium, causing a small, circumscribed elevation of the surface. Of. BLEB, BULLA. and POCK. 3. In botany, (a) a cell of vegetable ti ue; (6) an air-cavity or little bladder (e. g., one of the air-bladders in many Fucacece, which render the branches buoyant); and (e) a spore-v. [a, 35.] Adipose v. See Fat-cEL i,. Air v. 1. See ^ir-LACUNULE. 2. See -4i'r-CELL (1st def.) and ALVEOLUS (2d def.). 3. See V. (3d def. [6]). Air v's of the lungs. See Air v. (2d def.). Allaiitoic v. The internal, epithelial portion of the allantois. Anterior cephalic (or cerebral, or encephalic) v. Ger., vordere Hirnblase. A thin-walled cavity formed by the closing in of the dorsal laminae over the cephalic extremity of the primitive groove of the embryo and a subsequent transverse constriction at about the extremity of the notochord. From it are developed the cerebral hemispheres, pineal gland, pituitary body, corpus callosum, cerebral peduncles, fornix, and lateral and third ventricles. Subsequently it is divided by an antero-posterior cleft, which finally becomes the longitudinal fi ure. {L.] Antipodal v. See Antipodal CELL. As cher son i an v's. V's formed by shaking fluid fat and fluid albumin together, the latter forming a kind of investment or membrane for the minute globules of the fat. [J.] See also Hap toge no us MEMBRANE. Auditory v. See Otic v. Blastodermic v. See BLASTULA. Blood v's. Blood-corpuscles. [J.] Cerebral v's. See Encephalic v's. Contractile v. 1. An expansion of the lower end of the excretory canal of some of the Distomidce. [L, 16.] 2. See Contractile VACUOLE. Directing v. See Directing GLOBULE. Embryonal v., Embryonic v. Ger., Keimschlauch. See Embryonic CELL (4th def.). Encephalic v's. Lat., vesicula cephalic a. Ger., Hirnblaschen. The three compartments into which the anterior extremity of the primitive medullary tube is divided at an early period in foetal life. Other secondary v's spring from the primary one, from which are formed the organs of sense. [I, 15 (K).] Erythroid v. Fr., vesicule erythro'ide. Of Pockel, a vesicular structure described as constituting one of the elements of the ovum; pyriform, milky white, and larger than the umbilical vesicle; thought by Velpeau to be pathological. [A, 45.] Fat-v. See.Fat-CELL. Germinal v., Germinative v. 1. A somewhat spherical body in the ovum with an investing membrane, having fluid and granular contents with a protoplasmic network and germinal spot or spots; regarded e entially as a nucleus. [L, 142, 201.] See cut under OVUM. 2. In botany, the imperfectly formed germ-cell in the embryo-sac previous to fertilization, [a, 35.] Glandular v., Gland-v. See ACINUS (7th def.). Graafian v. Fr., vesicule de Graaf, poche vesicula ire. Ger., Eierstocksfollikel, Eiersack. A closed sac which contains the ovarian ovum. It consists of an external membrane lined with small granular cells (the membrana granulosa) which are condensed at one point to form the discus pro liger us. Prior to the ripening of the ovum the v. is situated within the stroma of the ovary, but as maturation advances it becomes superficial, its walls grow vascular, and it is distended with a serous fluid. It finally ruptures, allowing the ovum to escape. [L.] Kupffer's v. See Postanal v. Lens v. See Secondary ocular v. Malignant v. See Contagious ANTHRAX. Marginal v's. See Marginal BODIES. Medullary v. of the eye. See Primary optic v. Mesencephalic v., Middle cerebral (or encephalic, or primary) v. Ger., mittlere Hirnblase. In embryology, the dilatation of the medullary tube just posterior to the cephalic extremity of the notochord. from which the corpora quadrigemina, cerebral peduncles, and aqueduct of Sylvius are developed. [L.] Nuclear v. See NUCLEUS (1st def.). Ocular v's. See Primary optic v's. Olfactory v. The primitive v. from which is developed the olfactory lobe. [I, 2 (K).] Otic v. Ger., Gehorbldschen, Ohrblaschen, Gehorkapsel. The embryonic rudiment of the organ of hearing, formed by an involution of the epiblast from the outer surface of the head in the region of the medulla oblong at a, opposite the dorsal end of the hyoidean arch. [A, 5.] Ovarian v. See Graafian v. Polar v. See Extrusion GLOBULE. Pituitary v. The primitive pituitary body in the embryo. [1, 2 (K).] Postanal v. A vesicular dilatation of the posterior extremity of the postanal gut. [L, 201.] Posterior cephalic (or cerebral, or encephalic) v. The posterior enlargement of the medullary tube from which the cerebellum, pons Varolii, medulla oblong at a, and fourth ventricle are developed. [L.] Primary ocular (or optic) v's. Lateral projections from the anterior cerebral v., from which the eyes are developed. [L.] Primitive cerebral v. An expansion at the anterior extremity of the medullary tube, from which is developed the encephalon. It is subsequently divided into the anterior, middle, and posterior cerebral v's. [I, 28 (K); L.] Primitive optic v's. See Primary ocular v's. Prosenceplialic v. See Anterior cephalic v. Prostatic v. See UTERUS masculinus. Pulmonary v. See ^i>-CELL(lst def.) and ALVEOLUS (2d def.). Purkinjean v., Purkinje's v. See Germinal v. (1st def.). Secondary occipital v. See Posterior cerebral v. Secondary ocular (or optic) v. A depre ion, or involution, in the wall of the primary optic v., which receives the lens. [I, 15 (K).] Seminal v's. Lat., vesiculce semina les. Ger., Samenbldschen, Samenblascn, Samenai'cfcc/ien. Two membranous tubes, coiled and doubled upon themselves so as to present a sacculated appearance, and lying on the base of the bladder with their blind posterior extremities (between which the vasa deferent i a run) considerably separated. They converge toward the prostate and unite each with its corresponding vas deferens. They serve as receptacles for the semen. [L.] Sense-v. A v. from which an organ of special sense is developed. [LJ Spore-v.^ Lat., vesicula sporarum (seu sporidiorum)." Ger., Sporenblase. In the Physomycetes (vesicular molds),~s), one of the bladder-like fruits containing sporidia. [a, 35.] Un-Jmbilieal v. A, ape; A2, at; A3, ah; A. all; Ch, chin; Ch2, loch (Scottish); [s. 712]