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Show 224 DR. R. W. SHUFELDT ON [Apr. 1, found a short longitudinal gutter with a foraminal pit at either of it. Meckel's cartilage, as usual, is ensheathed by the anterior portion of the articular element of the mandible, from whence it proceeds forwards to the symphysis, being exposed along the inner side of the dentary for its anterior moiety. The angular, pointed behind and truncated in front, occupies nearly the middle third of the ventral border of the ramus. The two bones thus far alluded to are designated by Hoffmann as the articulare and the angulare, respectively. And it is m y intention in the present connection to use the nomenclature for the ramal elements given us by that distinguished anatomist (see Bronn's ' Thier-Reichs,' Rept. 22-24 Lief. 1881, Taf. lxvii. figs. 4-5), as his account of these ossifications is far more satisfactory than any other that I happen to have at my hand at the present moment. The coronoideum occupies its usual position, developing upon its mid-dorsal border a strong quadrate coronoid process, which takes on an upward and backward direction. This element articulates with the d,entale, the complement are, the operculare, and the articulare. Forming the base of a fossa between the bifurcations of the coronoideum, upon the mesial aspect of the ramus, occurs a thin splint-bone, the complementare, and this is probably the " splenial " element of some authors. Beyond the ossifications thus far described we find an operculare; it is a flat, irregular shaped bone that stands between the dentale on the one hand and the coronoideum, complementare, and the angulare on the other, forming a fair share of the mid-portion of the surface of the inner aspect of the ramus. Still more important is the dentale, which, as we know, bears the teeth. This is here quite a powerful bone forming the distal moiety of the mandible, being markedly concaved upon its mesial aspect, and correspondingly convexed both vertically and antero-posteriorly on its external surface. As I have already said, the symphysis of the two dentary elements is notably weak; indeed, the bones of the two sides are little more than in contact at the point in question. Two small foramina pierce the operculare upon its inner aspect, as does one the angulare posterior to these. Externally there is also an opening of this character which is found in the suture between the coronoideum and the articulare, being vertically below the coronoid process. The hyoid apparatus.-At its hinder extremity the slender basi-hyal is just sufficiently enlarged to admit of its articulation with the anterior and posterior cornua. Posterior to this point it does not send back any median process, while in front its delicate cartilaginous rod is continued forwards into the tongue. Upon either side of its hinder and slightly enlarged end it has articulating with it the mesial heads of the anterior cornua. These latter have their slender shafts at first directed, upon either side, forwards and outwards, when at a certain distance they are bent upon themselves, and then are directed outwards and backwards. At the point of flexion there appears to be some sort of a simple joint present. The posterior cornua are represented by paired bony rods of a |
