. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates. 414 COMPARATIVE AX ATOMY 318, A); these represent the remains of the sinu-auricular valves, arid in the embryo aid in conducting the blood from the right atrium into the Great variations are seen in the mode of origin of the carotids and subclavians from the arch of the aorta in Mammals. For example, there may be a brachiocephalic or innominate trunk on B C D K. Fio. 310.—FIVE DIFFERENT MODES OF ORIGIN OF THE UREAT VESSELS FROM THE ARCH OF THE AORTA IN MAMMALS. Ao, aortic arch ; , the, brachiocephalic trunk. either
. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates. 414 COMPARATIVE AX ATOMY 318, A); these represent the remains of the sinu-auricular valves, arid in the embryo aid in conducting the blood from the right atrium into the Great variations are seen in the mode of origin of the carotids and subclavians from the arch of the aorta in Mammals. For example, there may be a brachiocephalic or innominate trunk on B C D K. Fio. 310.—FIVE DIFFERENT MODES OF ORIGIN OF THE UREAT VESSELS FROM THE ARCH OF THE AORTA IN MAMMALS. Ao, aortic arch ; , the, brachiocephalic trunk. either side (Fig. 319, A) ; an unpaired common brachiocephalic, from which the carotid and subclavian of one or both sides arise (B, c, E) ; or a common trunk of origin for the carotids, the subclavians arising independently on either side of it (D). ARTERIAL SYSTEM. In Amphioxus, the ventral aorta, as in the Craniata, gives off a series of afferent branchial arteries, which are, however, in cor- respondence with the greater number of gill-clefts, much more numerous than in other Vertebrates. The afferent branchial vessels pass up the primary gill-bars, and give off branches to the secondary gill-bars (Fig. 258). and both series of branchial vessels open dorsally, as efferent branchial arteries, into a dorsal aorta on either side. The latter unites with its fellow posteriorly to the pharynx to form a median dorsal aorta, which gives off branches to the intestine, &c. The essential relations of the carotid arteries, dorsal aorta, and pulmonary arteries in the Craniata, as well as of the embryonic vitel- line arteries, have already been dealt with. Two carotids (usually described as anterior and posterior, or as internal and external) can usually be recognised in Fishes, arising independently on either side from the anterior afferent branchial arteries, but varying much in their arrangement (Figs. 304, 320,321): there may also be a ventral mandibular or lingual artery. From the A
Size: 3524px × 709px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectanatomycomparative
