CHORION

(Lat.), n. n. Gr., \6piov. Fr., c. Ger., Lederhaut, Aderhdutchen. It.,Sp., corion. 1. The external layer of the blastoderm; the outer enveloping membrane of the fecundated ovum, most characteristically developed in the human subject, being observed as soon as the ovum has entered the cavity of the uterus, and persisting through the whole period of gestation. A part of it takes a share in the development of the foetal portion or the placenta, and the remainder constitutes the outermost of the fostal envelopes. The c. of Purkinje, R. Wagner, A. Thomson, and W. Jones (i. e., the outer membrane of the unattached ovum in the uterus) is the exo chorion of Burdach and Velpeau, the membrana cortical is (Ger., Schalenhaut) and future exo chorion of von Baer, the Eihaut of Valentin, and the vitelline membrane of Coste and of Barry. [A, 4; A. Thomson (A, 5); L. 14, 142. 158, 201.] 2. The corium. 3. The zona pellucid a. 4. The foetal placenta. 5. As improperly applied, the ovisac of certain of the lower vertebrates. [Barry, "Phil. Trans.," 1838, ii (L).] 6. Of Haller (according to some), the decidua reflex a. [A, 45.] 7. In botany: o. The outer membrane of the seeds of plants, b. A carpel, c. The pulpy liquid in the interior of a seed before impregnation. [B, 1, 19, 116 (o. 24).] Blastodermic c. Fr., c. blastoderm i que. See Secondary c. Bleibendes C. (Ger.). See Secondary c. C'ahnlich (Ger.). Resembling the c. or the chorioid. [L, 349.] C. anhiste (Fr.). See Primitive c. C'baumchen (Ger.). An a emblage of umbilical blood-ve els ramifying in the chorionic villi. [Kcilliker (H).] C. blastoderm i que (Fr.). See Secondary c.C. blastodermiqueallantoldien (Fr.), C. blastodermo-allantoidien (Fr.), C. rumpus*'- cleflnitif (Fr.). See Vascular c.C. de I'o3uf (Fr.). See Primitive c.C. des Eierstockseies (Ger.). See ZONA pellucid a. C. fila men to sum, C. flocculentum, C. frondosum. See Shaggy c.C. fungosum. Of some of the older writers, the decidua reflex a. [A. 45.] C. glabrum, C. laeve. See False c. C. mon epithelial (Fr.). See Secondary c.C. muqueux (Fr.). See CORIUM. C. ovulaire (Fr.), C. pellucidum, C. primitivum. See Primitive c.C. reticula tum, C. reticulosum. See Shaggy c.C. secundarium, C. se>eux (Fr.). See Secondary c. C. se>eux-allantotdien (Fr.). See Vascular c. C. spongiosuiti. Ger., Schwammiges C. 1. The shaggy c. 2. According to some of the older writers, the decidua rflexa. [A, 45.] C's pro en (Ger.). The chorionic villi, especially the branches of the E, he; E2, ell; G, go; I, die: I2, in: N, in: N*. tank; [s. 260]