. Text book of zoology. Zoology. 386 Vertehrata. ventral to the long, bent-up poi-tion of the spinal column (Fig. 299 B). Rhom- boidal scales. Several species in N. America. 3. Amia. Externally almost exactly like a Teleostean; it has cycloid scales. For its chief characteristics see p. 375, foot-note * : p. 377, foot-note *; Fig. 304 C; Fig. 310 B. It occui-s in North America. Order 4. Dipnoi. TKe skeleton is partially ossified; the conus arteriosus spirally coiled and provided inside with a longitudinal fold formed of modified valves; a spiral valve in the intestine; the operculum is support
. Text book of zoology. Zoology. 386 Vertehrata. ventral to the long, bent-up poi-tion of the spinal column (Fig. 299 B). Rhom- boidal scales. Several species in N. America. 3. Amia. Externally almost exactly like a Teleostean; it has cycloid scales. For its chief characteristics see p. 375, foot-note * : p. 377, foot-note *; Fig. 304 C; Fig. 310 B. It occui-s in North America. Order 4. Dipnoi. TKe skeleton is partially ossified; the conus arteriosus spirally coiled and provided inside with a longitudinal fold formed of modified valves; a spiral valve in the intestine; the operculum is supported by bony plates; the lung is functional; the skin provided with scales, the fins with unsegmented, soft, bony rays. Both anterior and posterior nares lie within the mouth. The limbs are either long, pointed plates, with a median, segmented, cartila- ginous rod, from either side of which a series of cartilaginous rays arise; or they are filiform, with a similar, but more or less reduced skeleton. The tail is pointed and diphycercal; notochord uncon- stricted and well-developed; a few large teeth in the mouth. Exclusively freshwater. This aberrant group, which at the present day is represented by a few forms only, is most nearly allied to the Ganoids, especially the Holostei. The structure of the conus is remai-kable, recalling the condition in the Amphibia {}.); in connection with it are certain peculiarities in the structure of other parts of the heart, by which a partial separation of blood from the lung and from the rest of the body is effected. The structure of the limbs, the position of the nares, etc., is also very Fig. 316. After Giinther. 1. The Mud-fish or Barramunda (Ceratodus) is a large, elongate animal, pointed at both ends; with large scales; large, broad limbs; dorsal, caudal and anal fins continuous. It inhabits the rivers of Please note that these images are extracted from scanned page images that may have been digitally e
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectzoology, bookyear1896
