Fig. 16.—Ventral view of Skull of Xenopus and Rana.
[In the Frog there are a pair of vomers bearing the vomerine teeth, palatines, and quadrato-jugals. The pro-otics, which are not seen in a ventral view of the skull in the Platana, being covered over by the pterygoids, are shown in the Frog.]
Make a drawing of the ventral side of the skull.
Fig. 17.—Side view of Skull of Xenopus and Rana.
3. Make a drawing of the bones of the skull viewed from the posterior end, showing the occipital condyle at each side of the foramen magnum, ex-occipitals, basi-occipital, supra-occipital, pro-otics, columella, and quadrate.
[In the Frog the basi-occipital and supra-occipital are not developed.]
4. Remove the skin from the lower jaw and make out the bones surrounding the original Meckel's cartilage, viz., the mento-meckelian, dentary, and articular.
[In the Frog the lower jaw is composed of the mento-meckelian, dentary and angulo-splenial.]