. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. CIRCULATORY ORGANS. 291 portion of which now forms a new trunk, carrying blood from the posterior part of the body to the heart (figs. 294, 295). With the appearance of the postcava changes are introduced in the embryonic renal portal circulation ( p. 280) which may be summarized as follows: The subcardinals lose their connexion with the caudal vein and become connected with each other by transverse vessels (interrenal veins) while parts of the postcardinals adjacent to the nephridial organs separate from the p
. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates -- Anatomy. CIRCULATORY ORGANS. 291 portion of which now forms a new trunk, carrying blood from the posterior part of the body to the heart (figs. 294, 295). With the appearance of the postcava changes are introduced in the embryonic renal portal circulation ( p. 280) which may be summarized as follows: The subcardinals lose their connexion with the caudal vein and become connected with each other by transverse vessels (interrenal veins) while parts of the postcardinals adjacent to the nephridial organs separate from the parts in front, while they grow backward. FIG. 295.—Development of postcaval system in birds (A, B, sparrow; C, D, chick), schematized after A. M. Miller. In A the postcardinals have extended nearly to the pelvic region and the subcardinals are appearing as isolated spaces. In B the subcardinal spaces are uniting and the capillary system connecting with the postcardinals is developing, while the postcava is arising. In C the postcava has united with the subcardinal of the right side, ai, ischiadic artery; aie, external iliac artery; au, umbilical (hypogastric) artery; da, dorsal aorta; m, mesonephric veins; om, omphalomesenteric artery; p, postcava and its anlagen; sc, subcardinal and its elements; vei, external iliac vein; vi, ischiadic vein. and connect with the caudal vein (fig. 295). These posterior parts of the postcardinals now become the advehent veins of a second renal portal system, bringing blood from the tail and hind limbs to the excretory organs (mesonephroi). The subcardinals of the two sides usually fuse in the middle line, a process initiated by the appearance of the interrenal veins, and now act as a revehent vessel, carrying blood from the excretory organs to the postcava and the anterior. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustration
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Keywords: ., bookcentury1900, bookdecade1910, booksubjectanatomy, bookyear1912
