. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates. 404 COMPARATIVE ANATOMY Neither in Vrodela nor Anura is there a .septum ventriculorum, so that the blood passing out from the spongy ventricle must have a mixed character (Fig. 306). The ventricle is usually short and compressed, but is more elongated in Amphiuma, Proteus, and the Gymnophiona. It is continued anteriorly into a conus arteriosus; this has usually a slight spiral t\vist, and possesses a transverse row of valves at either end, as well as a spiral fold, formed by a fusion of valves and extending into its lumen
. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates. 404 COMPARATIVE ANATOMY Neither in Vrodela nor Anura is there a .septum ventriculorum, so that the blood passing out from the spongy ventricle must have a mixed character (Fig. 306). The ventricle is usually short and compressed, but is more elongated in Amphiuma, Proteus, and the Gymnophiona. It is continued anteriorly into a conus arteriosus; this has usually a slight spiral t\vist, and possesses a transverse row of valves at either end, as well as a spiral fold, formed by a fusion of valves and extending into its lumen, thus partially dividing it into a dorsal pidmoncde, and a ventral caw in aortictim communicating with the carotid and systemic /. ft. j. a. Try/. FIG. 307.—HEART OF Cryptdbranchiis japonicus. From the ventral side, i After Rose.) The left atrium is cut open. , , the t\vo pulmonary veins, opening by a single aperture into the left atrium ; L. Vh, P. Vh, left and right atria ; , atrio-ventricular aperture ; and P.*, left and right pulmonaiy arteries ; , septum atriorum, perforated by numerous small apertures; tr, truncus arteriosus; , posterior cardinal veins; r.*, postcaval vein; and !"../.«, jugular veins; V.*.d and !".>.•>-, subclavian veins; 1", 4", the four arterial arches. arches. This holds' good, , for Amblystoma, Salamandra, Amphiuma, and Siren. In others ( Necturus, Proteus, Gymnophiona), the conus is more elongated, and reduction is seen in the disappearance of the spiral fold and the presence of only a single row of valves. In Anura, the fold lying within the conus extends so far back that no undivided portion of the cavity is left. The consequence of this is that the blood passing into the hindermost pair of the arterial arches—that from which the pulmonary arteries arise—is mainly venous, while the others contain more or less mixed blood. Please note that these images are e
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectanatomycomparative
