. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Intake Apparatus 283 --°-^Basibranchials tongue. The mechanism in the two cases is somewhat different. In Cham- eleon the bony framework of the primary tongue acts as a system of exten- sible levers to supplement the secondary muscular component of the tongue in its protrusion, which is not the case with Eurycea. In birds the bony framework of the primary tongue, which supports the secondary tongue, is especially well developed. This framework consists typ
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. Intake Apparatus 283 --°-^Basibranchials tongue. The mechanism in the two cases is somewhat different. In Cham- eleon the bony framework of the primary tongue acts as a system of exten- sible levers to supplement the secondary muscular component of the tongue in its protrusion, which is not the case with Eurycea. In birds the bony framework of the primary tongue, which supports the secondary tongue, is especially well developed. This framework consists typically of a median bone or bones, the copula (Fig. 235), and two pairs of lateral bones, the small hyoids, and the first branchials, all of which are relics of ancestral gill arches. Its movement is facilitated by means of extrinsic muscles attached to these bones, the intrinsic muscles of the secondary tongue being reduced or absent. A woodpecker, whose horny spearlike tongue can be projected out of the long beak when impaling a grub in the bark of a tree, possesses an elaborate skeletal hyoid apparatus attached at the base of the tongue, and with long posterior horns (first branchials) lying just beneath the skin. When at rest each of these horns extends from the tongue into the neck, then dorsally and forward over the top of the skull, reaching even into the base of the beak (Fig. 236). As the tongue is extended the springy supporting hyoid coils are straightened out through the action of muscles, while the withdrawal of the tongue to its original posi- tion within the beak is accomplished by the elasticity of the hyoids which snap back into place like released watch-springs that have been temporarily straight- ened out. The mammalian tongue, like that of reptiles, is made up of two parts. The anterior region, somewhat rough and covered with numerous small elevations (papillae) of various shapes, is separated from the posterior part, bumpy in appearance due to masses of lym
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Keywords: ., bookcentury1900, booksubjectanatomycomparative, booksubjectverte
