78. The bones of the cranium are united by ragged edges, called _sut´ures_. The edges of each bone interlock with each other, producing a union, styled, in carpentry, _dovetailing_. They interrupt, in a measure, the vibrations produced by external blows, and also prevent fractures from extending as far as they otherwise would, in one continued bone. From infancy to the twelfth year, the sutures are imperfect; but, from that time to thirty-five or forty, they are distinctly marked; in old age, they are nearly obliterated. [Illustration: Fig. 7. 1, 1, The coronal suture at the front and upper part of the skull, or cranium. 2, The sagittal suture on the top of the skull. 3, 3, The lambdoidal suture at the back part of the cranium.] 79. We find as great a diversity in the form and texture of the skull-bone, as in the expression of the face. The head of the New Hollander is small; that of the African is compressed; while the Caucasian is distinguished for the beautiful oval form of the head. The Greek skulls, in texture, are close and fine, while the Swiss are softer and more open. -=-=-=-=-=-=-=-=-=-=-=-= 78. How are the bones of the skull united? What are the uses of the sutures? Mention the appearance of the sutures at different ages. What does fig. 7 represent? 79. What is said respecting the form and texture of the skull in different nations? -=-=-=-=-=-=-=-=-=-=-=-= 80. In each EAR are four very small bones. They aid in hearing. 81. In the FACE are fourteen bones, some of which serve for the attachment of powerful muscles, which are more or less called into action in masticating food; others retain in place the soft parts of the face. [Illustration: Fig. 8. 1, The frontal, or bone of the forehead. 2. The parietal bone. 3, The temporal bone. 4, The zygomatic process of the temporal bone. 5, The malar (cheek) bone. 6, The superior maxillary bone, (upper jaw.) 7, The vomer, that separates the cavities of the nose. 8, The inferior maxillary bone, (lower jaw.) 9. The cavity for the eye.] 82. The TRUNK has fifty-four bones--twenty-four _Ribs_; twenty-four bones in the _Spi´nal Col´umn_, (back-bone;) four in the _Pel´vis_; the _Ster´num_, (breast-bone;) and the _Os hy-oid´es_, (the bone at the base of the tongue.) They are so arranged as to form, with the soft parts attached to them, two cavities, called the _Tho´rax_ (chest) and _Ab-do´men_. -=-=-=-=-=-=-=-=-=-=-=-= 80. How many bones in the ear? 81. How many bones in the face? What is their use? Explain fig. 8. 82-94. _Give the anatomy of the bones of the trunk._ 82. How many bones in the trunk? Name them. What do they form by their arrangement? -=-=-=-=-=-=-=-=-=-=-=-=