. The American journal of anatomy . ear in the a final procedure will become clearer in the consideration ofthe second or transition phase. (C) Supracardinal division. In the region of the mesonephroi,plexuses of vessels spring from the ventral aspect of the supra-cardinal veins, and in some embryos they become so extensiveas to encompass the aorta almost completely. For this reasonand the fact that they are the equivalents of the anterior veno-lymphatics in function, they were named the supracardinal peri-aortic veno-lymphatics. A further description of them would besuperfluou
. The American journal of anatomy . ear in the a final procedure will become clearer in the consideration ofthe second or transition phase. (C) Supracardinal division. In the region of the mesonephroi,plexuses of vessels spring from the ventral aspect of the supra-cardinal veins, and in some embryos they become so extensiveas to encompass the aorta almost completely. For this reasonand the fact that they are the equivalents of the anterior veno-lymphatics in function, they were named the supracardinal peri-aortic veno-lymphatics. A further description of them would besuperfluous considering their clearness in the accompanying micro-photograph and reconstruction (6c, figs. 3 and 32). Caudally, at the level of the superior mesenteric artery, sub-sidary channels arise from the supracardinalsventro-medially,become more and more plexiform, and approach one another fromboth sides to anastomose in the area dorsad of the aorta (6c,fig. 4). Since eventually they will be concerned in the pro- 422 OTTO F. KAMPMEIER. Fig. 3 Transverse section through the region just in front of the mesonephroiin a 19 mm. embryo (series 168, slide 23, section 17), X 150. 6c, supracardinalperiaortic veno-lymphatics in the positions of the later right and left thoracicducts; lid, lis, right and left postcardinals; 12d, 12s, right andleft supracardinals;13, aorta; 17, oesophagus. (Reconstructions, figs. 28 and 32.) duction of the most posterior segment of the thoracic duct, orcisterna chyli, they may be labelled posterior supracardinalveno-lymphatics. Situated topograpically in the pathway of the future thoracicduct, all of the veno-lymphatics mentioned in the three divisionswould be said to give rise to it directly, or to be transformed intoit, were the second or transition phase of its history leads up to the suggestion that Lewis and temporarily alsoMcClures multiple endothelial-lined anlagen derived from theveins along which they lie are nothing more and nothing
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1912
