. An introduction to the osteology of the mammalia . FIG. 45.—Sternum and ribs of the Great Armadillo (Priodou gigas), \.ps presternum ; xs xiphisternum. In the MONOTREMATA the intermediate ribs are wellmarked (see Fig. 44, p. 105), and only partly ossified byendostosis, while the sternal ribs (except the first) are,according to Parker, strongly ossified ectosteally, as in Birds. VIII.] MONO TREMA TA. The hinder sternal ribs are very broad and flat. TheEchidna has 16, and the Ornithorhynchus 17 pairs ofvertebral ribs; they do not divide above into head andtubercle, but are attached only to the
. An introduction to the osteology of the mammalia . FIG. 45.—Sternum and ribs of the Great Armadillo (Priodou gigas), \.ps presternum ; xs xiphisternum. In the MONOTREMATA the intermediate ribs are wellmarked (see Fig. 44, p. 105), and only partly ossified byendostosis, while the sternal ribs (except the first) are,according to Parker, strongly ossified ectosteally, as in Birds. VIII.] MONO TREMA TA. The hinder sternal ribs are very broad and flat. TheEchidna has 16, and the Ornithorhynchus 17 pairs ofvertebral ribs; they do not divide above into head andtubercle, but are attached only to the sides of the bodiesof the vertebrae. The last 5 sternal ribs of Echidna, especi-ally E. bruijni, are exceedingly broad and overlap I 2 CHAPTER IX. THE SKULL. THE skull is the term commonly applied to the expandedanterior portion of the axial skeleton situated within thehead. It consists mainly of the cranium, a strong bony case orframe, enclosing the brain, and affording support and pro-tection to the organs of smell, sight, hearing, and taste, andformed by the close union, either by sutures or by synostosis,of numerous bones. To the inferior surface of the cranium are suspended (i)the Mandible, or lower jaw, movably articulated by a syno-vial joint; and (2) a group of skeletal structures called thehyoidean apparatus. The diagram at p. 126 is intended, to show at a single viewthe names applied to the various bones of which the skull iscomposed, and to give some idea of their relative position. It will be well to commence the study of the skull bydescribing that of a Dog, as a good average specimen of theclass, and one which is easily procurable at various ages ,and the student is strongly advised to follow the de
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectbones, bookyear1885
