. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. 360 Biology of the Vertebrates. lungs (Fig. 297), and not on the left side where it is popularly located by tragic actors and sentimental lovers. The reason it seems to be on the left side is because the throbbing tip of the cone-shaped ventricular part nor- mally projects from behind the sternum towards the left side, where its kick is most readily felt. There are many misconceptions cen- tering around the human heart. For instance, it is never "hear
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. 360 Biology of the Vertebrates. lungs (Fig. 297), and not on the left side where it is popularly located by tragic actors and sentimental lovers. The reason it seems to be on the left side is because the throbbing tip of the cone-shaped ventricular part nor- mally projects from behind the sternum towards the left side, where its kick is most readily felt. There are many misconceptions cen- tering around the human heart. For instance, it is never "heart-shaped" ac- cording to the conventional Saint Valen- tine's outline, but instead is a flattened cone. 5. Valves The most constant valves of the heart in the vertebrate series are the auriculo- ventricular valves, which separate the re- ceiving auricle from the forwarding ven- tricle. They are present in all vertebrates and, in higher forms, are kept from re- versing under the pressure of the con- tracting ventricle by tendon-like guys, chordae tendineae, that are anchored in the muscular walls of the ventricle (Fig. 298). There are only two such valves in the heart of fishes but in the double heart of mammals there are five present, two between the auricle and ventricle of the left side {bicuspid valves) and three (tricuspid valves) on the right side. The bicuspid valves are commonly known as mitral valves from a fancied resemblance to a bishop's miter. It was Huxley who once humorously said that he could always easily remember the location of the mitral valves on the left side of the heart because he "never knew a bishop to be on the right ; The semilunar valves of the conus region are best seen in elasmo- branchs and ganoids, where as many as eight rows may appear in some species (Fig. 294a and b). They are cuplike pockets, lying flat against the inner wall as the blood passes out over them, but filling immediately to block the passage-way when the blood
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