Section 26. Figure 2 Shows a Dorsal View of These Structures in a

young frog. The parts corresponding to these in 1,II. will be easily made out, but now ossification has set in at various points of this cartilaginous cranium. In front of the otic capsule is the paired pro-otic bone (p.o.); behind it at the sides of the parachordal ring is the paired ex-occipital (e.o.); in front of the cranium box, and behind the nasal capsules, is a ring of bone, the (median, but originally paired) sphenethmoid (s.e.). -A paired ossification appears in the palato-pterygoid cartilage the pterygoid bone (pt.), while- A splint of bone, the quadrato-jugal, appears at the angle of articulation with the lower jaw. These are all the cartilage bones that appear in the cranium and upper jaw of the frog.