. On the anatomy of vertebrates [electronic resource] . fig. 97(Vol. I.) to the dentigerous haemapophysis, si. The proximal arti-cular end of the tympanic may have a double condyle, as in someFishes and Birds, a single condyle, as in Lizards and Serpents, or asutural margin for fixed junction, as in Chelonia, fig. 91, 28, andCrocodilia, fig. 95, 28. Such is its mode of articulation in all Mam-mals, in which class it manifests its extreme simplicity of functionand reduction of size. To the ear-drum, which it sustains, isarticulated, in Birds, a columelliform f stapes, by the intermediumof a car
. On the anatomy of vertebrates [electronic resource] . fig. 97(Vol. I.) to the dentigerous haemapophysis, si. The proximal arti-cular end of the tympanic may have a double condyle, as in someFishes and Birds, a single condyle, as in Lizards and Serpents, or asutural margin for fixed junction, as in Chelonia, fig. 91, 28, andCrocodilia, fig. 95, 28. Such is its mode of articulation in all Mam-mals, in which class it manifests its extreme simplicity of functionand reduction of size. To the ear-drum, which it sustains, isarticulated, in Birds, a columelliform f stapes, by the intermediumof a cartilage ; and in Monotremes and Marsupials, fig. 197, d, bythe intermedium of a bone, c. This ossicle in higher Mammals isdivided into 6 incus and 4 malleus, which, like the columelliform< stapes in Birds and Reptiles, is developed, as in fig. 444, b, e(Vol. I.), in connection with, but not like the tympanic (d) andmandible in and from, the periphery of the primary visceralor haemal cartilaginous arch, called, from its discoverer, 316 ANATOMY OF VERTEBRATES. Having premised so much in reference to the Mammalianskeleton generally or typically, its main modifications as exem-plified in the several orders of the class, will next be noticed. § 179.—Skeleton of Monotremata.—A. Vertebral Column.—Theprincipal osteological characters of this order are:—The extensionof the i coracoid, fig. 199, 52, o, as in Birds and Lizards, from thescapula, 51, to the sternum, s, and anchylosing at full growth withthe scapula, as at G, fig. 199 ; the epicoracoid, ib. n, as in Lizards ;the marsupial bones, ib. x, x; the supplementary tarsal bone,ib. d, supporting the perforated spur, e, in the male; the longpersistence of distinct pleurapophyses, pi, in the vertebra clentata. Both the genera have twenty-six (true vertebrae, of whichOQ0 seven are cervical; but the Ornithorhynchus has seventeen and the Echidna sixteen dor-
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