. A guide to the study of fishes. Fishes; Zoology; Fishes. The Ganoids IS with very long dorsal and anal fins. In other respects they are very similar to the PalmoniscidcB, the osteology being the same. The PalcBoniscidcB were rapacious fishes with sharp teeth, the PlatysomidcB less active, and, from the blunter teeth, probably feeding on small animals, as crabs and snails. The rhombic enameled scales are highly specialized and held together as a coat of mail by peg-and-socket joints. The most extreme form is Platysomus, with the body very deep. Platysomus gihbosus and other species occur in t
. A guide to the study of fishes. Fishes; Zoology; Fishes. The Ganoids IS with very long dorsal and anal fins. In other respects they are very similar to the PalmoniscidcB, the osteology being the same. The PalcBoniscidcB were rapacious fishes with sharp teeth, the PlatysomidcB less active, and, from the blunter teeth, probably feeding on small animals, as crabs and snails. The rhombic enameled scales are highly specialized and held together as a coat of mail by peg-and-socket joints. The most extreme form is Platysomus, with the body very deep. Platysomus gihbosus and other species occur in the Permian rocks of Germany. Cheirodus is similar to Platysomus, but without ventral fins. Eurynotus, the most primitive genus, is remarkable for its large pectoral fins. Eurynotus crenatus occurs. Fig. 3.—Eurynotus crenatus Agassiz, restored. Carboniferous. Family PlatysomidcE. (After Traquair.) in the Subcarboniferous of Scotland. Other genera are Meso- lepis, Globulodus, Wardichthys, and Cheirodopsis. Some of the PlatysomidcB have the intemeural spines pro- jecting through the skin before the dorsal fin. This condition is found also in certain bony fishes allied to the Carangidce. The Dorjrpteridae.—Dorypterus hoffmani, the type of the sin- gular Palaeozoic family of DorypteridcB, with thoracic or sub- jugular many-rayed ventrals, is Stromateus-like to all appear- ance, with distinct resemblances to certain Scombroid forms, but with a heterocercal tail like a ganoid, imperfectly ossified back-bone, and other very archaic characters. The body is apparently scaleless, unlike the true PlatysomidcB, in which the. 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 Jordan, David Starr, 1851-1931. New York, H. Holt
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