. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. s Pelvic Fin Fig. 327. External gills in a larval stage of Lepidosiren. (After Kerr.) 6. Dipnoan Gills Of the three genera of living lungfishes that are found respectively in Australia, South America, and Africa, Neoceratodus has four pairs of gills, Lepidosiren, three, and Protopterus, two. Spiracles are present in the embryos of these fishes, although not in the adults. In addition to the pharyngeal gills common to this group, four pairs of supplemental
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. s Pelvic Fin Fig. 327. External gills in a larval stage of Lepidosiren. (After Kerr.) 6. Dipnoan Gills Of the three genera of living lungfishes that are found respectively in Australia, South America, and Africa, Neoceratodus has four pairs of gills, Lepidosiren, three, and Protopterus, two. Spiracles are present in the embryos of these fishes, although not in the adults. In addition to the pharyngeal gills common to this group, four pairs of supplemental true external gills of the pinnate (pinna, feather) type are present in the larval stages of Lepidosiren and Protopterus (Fig. 327). 7. -r- Brain. Internals Carotid Efferent N Branchial Gills"" Afferent Bronchia ^Pharynx ^Pericardial Cavity Amphibian Gills The external gills of amphibians are attached as capillary detours upon the aortic loops in such a way that blood can go either directly around the vascular loops or round- about through the gills (Fig. 328). This is quite different from the arrange- ment of the internal gills of fishes, which offers no alternative for the circu- lating blood except to pass through the gills themselves. Anastomosis Fig. 328. Section through branchial re- gion of a 6 mm larva of Rana esculenta, showing vascular loop„ in external gills and anastomosis between afferent and efferent branchial arteries. (After Maurer.). Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Walter, Herbert Eugene, b. 1867; Sayles, Leonard Perkins, 1902-. New York : Macmillan Co.
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