R. The inferior vena cava about to enter its notch in the posterior thick part of the liver, to receive the hepatic veins. S. The gall-bladder, communicating by its duct with the hepatic duct, which is lying upon the vena portae, and by the side of the hepatic artery. T. The pyloric end of the stomach, joining T*, the duodenum. U. The spleen. V V. The pancreas. W. The sigmoid flexure of the colon. X. The caput coli. Y. The mesentery supporting the numerous looping branches of the superior mesenteric artery. Z. Some coils of the small intestine. 2. Innominate artery. 3. Right subclavian artery. 4. Right common carotid artery. 5. Left subclavian artery. 6. Left common carotid artery. 7. Left axillary artery. 8. Coracoid attachment of the smaller pectoral muscle. 9. Subscapular muscle. 10. Coracoid head of the biceps muscle. 11. Tendon of the latissimus dorsi muscle. 12. Superior mesenteric artery, with its accompanying vein. 13. Left kidney. [Illustration: Chest and abdomen, showing bones, blood vessels, muscles and other internal organs.] Plate 24 COMMENTARY ON PLATE 25. THE RELATION OF THE PRINCIPAL BLOODVESSELS OF THE THORAX AND ABDOMEN TO THE OSSEOUS SKELETON, ETC. The arterial system of vessels assumes, in all cases, somewhat of the character of the forms upon which they are distributed, or of the organs which they supply. This mode of distribution becomes the more apparent, according as we rise from particulars to take a view of the whole. With the same ease that any piece of the osseous fabric, taken separately, may be known, so may any one artery, taken apart from the rest, be distinguished as to the place which it occupied, and the organs which it supplied in the economy. The vascular skeleton, whether taken as a whole or in parts, exhibits characteristics as apparent as are those of the osseous skeleton itself. The main bloodvessel, A B C, of the trunk of the body, possesses character, sui generis, just as the vertebral column itself manifests. The main arteries of the head or limbs are as readily distinguishable, the one from the other, as are the osseous fabrics of the head and limbs. The visceral arteries are likewise moulded upon the forms which they supply. But evidently the arterial system of vessels conforms most strictly with the general design of the osseous skeleton.