. Fishes. Fishes. 30 The Dissection of the Fish lived, and some may be even annual, dying after spawning, per- haps at the end of the first season. Teeth are wholly absent in several groups of fishes. They are, however, usually present on the premaxillary, dentary, and pharyngeal bones. In the higher forms, the vomer, palatines, and gill-rakers are rarely without teeth, and in many cases the pterygoids, sphenoids, and the bones of the tongue are similarly armed. No salivary glands or palatine velum are developed in fishes. The tongue is always bony or gristly and immovable. Some- times taste-b
. Fishes. Fishes. 30 The Dissection of the Fish lived, and some may be even annual, dying after spawning, per- haps at the end of the first season. Teeth are wholly absent in several groups of fishes. They are, however, usually present on the premaxillary, dentary, and pharyngeal bones. In the higher forms, the vomer, palatines, and gill-rakers are rarely without teeth, and in many cases the pterygoids, sphenoids, and the bones of the tongue are similarly armed. No salivary glands or palatine velum are developed in fishes. The tongue is always bony or gristly and immovable. Some- times taste-buds are developed on it, and sometimes these are found on the barbels outside the mouth. The Alimentary Canal.—The mouth-cavity opens through the pharynx between the upper and lower pharyngeal bones into the. Fig. 19.—Sheepshead (with incisor teeth"), Archosargus probatocephalus (Wal- baum). Beaufort, N. C. oesophagus, whence the food passes into the stomach. The intes- tinal tract is in general divided into four portions—oesophagus, stomach, small and large intestines. But these divisions of the intestines are not always recognizable, and in the very lowest forms, as in the lancelet, the stomach is a simple straight tube without subdivision. In the lampreys there is a distinction only of the oesoph- agus with many longitudinal folds and the intestine with but. 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 and Company
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