1. The Cranium Proper or Brain Case.

Taking the membrane and cartilage bones together, they are seen to be more or less arranged in three segments, which however must not be regarded as homologous with the segments forming the vertebral column.

Fig. 71. Diagram of the relations of the principal bones in the

Mammalian Skull (modified after Flower).

Cartilage is dotted. Cartilage bones are marked by dots and dashes,

membrane bones are left white.

1. basi-occipital.15. mesethmoid.
2. exoccipital.16. vomer.
3. supra-occipital.17. pterygoid.
4. basisphenoid.18. palatine.
5. alisphenoid.19. maxillae.
6. parietal.20. premaxillae.
7. presphenoid.21. squamosal.
8. orbitosphenoid.22. mandible.
9. frontal.23. tympano-hyal.
10. periotic, immediately below24. stylo-hyal.
which is the tympanic.25. epi-hyal.
11. lachrymal.26. basi-hyal. Between this and
12. ethmo-turbinal.the epi-hyal is the cerato-hyal.
13. maxillo-turbinal.27. thyro-hyal.
14. nasal.28. jugal.

Nerve exits are indicated by Roman numerals.