=====================+=====+=====+=====+=====+=====+=====+==== Bone |Stage|Stage|12.6 |13.9 |32.0 |27.0 |20.1 | 40 | 44 | mm. | mm. | mm. | mm. | mm. ---------------------+-----+-----+-----+-----+-----+-----+---- Frontoparietal | X | X | X | X | X | X | X Parasphenoid | X | X | X | X | X | X | X Septomaxillaries | X | X | X | X | X | X | X Exoccipitals | X | X | X | X | X | X | X Squamosals | -- | X | X | X | X | X | X Premaxillaries | -- | X | X | X | X | X | X Maxillaries | -- | X | X | X | X | X | X Nasals | -- | -- | X | X | X | X | X Pterygoids | -- | -- | X | X | X | X | X Vomers | -- | -- | -- | X | X | X | X Palatines | -- | -- | -- | X | X | X | X Quadratojugals | -- | -- | -- | X | X | X | X Ethmoid | -- | -- | -- | -- | X | X | X Columellas | -- | -- | -- | -- | X | X | X Supraorbital Flanges | -- | -- | -- | -- | -- | X | X Prooetics | -- | -- | -- | -- | -- | -- | X Vomerine Teeth | -- | -- | 1/1 | 4/3 | 5/5 | 3/3 | 5/4 Maxillary Teeth | -- | 0/7 | 3/5 | 6/5 |30/31|30/26|37/36 Premaxillary Teeth | -- | 2/4 | 3/3 | 5/5 | 7/6 | 8/6 | 8/7 ---------------------+-----+-----+-----+-----+-----+-----+---- The dentigerous bones are among the most rapidly developed, although not the first to appear. They are present in developmental stage 44 before metamorphosis is completed. The maxillaries bear a few teeth anteriorly and are ossified posteriorly to a point one-third of the distance from the anterior to the posterior edge of the orbit. Ossification lengthens the posterior termini of the maxillaries to the posterior edge of the orbit. In front of the anterior margin of the orbit, bone is proliferated dorsal to the main axes of the maxillaries and forms moderate dorsal maxillary flanges. The premaxillaries appear simultaneously with the maxillaries. Initially they are widely separated medially from each other, and laterally from the developing maxillaries; each bears two or three teeth, large dorsally blunt alary processes, and small palatine processes. The median and lateral edges of the prenasal processes lengthen heterochronously, causing the median edges to be longest and to lie slightly dorsal to the level of the septomaxillaries. After the maxillaries and premaxillaries develop, the vomers appear as small horizontal ossifications anterior to the parasphenoid. Ossification begins in the lateral flanges, then in the prevomerine processes, and lastly in the posterior dentigerous parts of the bones; the prevomerine processes are the last parts of the vomers to ossify completely.