Section III—Mouth, Oral Cavity, and Pharynx
Open the oral cavity and pharynx by cutting from each corner of the mouth posteriorly through the gills. Swing open the lower jaw, as shown in Figure 5.10, to expose the oral cavity and pharynx.
These regions are not distinctly demarcated. Note the teeth, arranged in V-shaped rows in the anterior part of the oral cavity. In the upper jaw, the most anterior row contains premaxillary teeth. Just behind these teeth are the vomerine teeth medially and the pterygoid teeth laterally. An internal choana, the internal opening of the nasal passage, may be seen on each side of the roof of
(d) Pelvic girdle right lateral view
FIGURE 5.8 Pelvic girdle and hind limbs of the mudpuppy in (a) dorsal view, (b) closeup of pelvic girdle in dorsal view, (c) closeup of pelvic girdle in ventral view, and (d) right lateral view.
FIGURE 5.9 External features of the mudpuppy in left lateral view.
FIGURE 5.10 Oral cavity and pharynx of the mudpuppy.
the oral cavity, just lateral to the pterygoid teeth. In the lower jaw there is a single row of teeth. Most of them are dentary teeth; a few splenial teeth lie near the posterior end of the row. The tongue, supported by the hyoid arch, lies behind these teeth. Identify the sectioned surfaces of the hyoid arch and mandibular arch. The entrances of the pharyngeal slits into the pharynx may be noted on each side. Probe to verify that there are two slits. Midventrally on the floor of the pharynx, between the entrances to the slits, is the glottis, a small, slit-like opening into the respiratory system.
Key Terms: Mouth, Oral Cavity, and Pharynx
dentary teeth glottis hyoid arch internal choana mandibular arch oral cavity
pharynx premaxillary teeth pterygoid teeth splenial teeth tongue vomerine teeth