. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. AMPHIBIA. 99 attached to the cranium ; (jig. 25, a,) the single piece (/>,) and the two rhomboidal pieces (r, r,) in the meantime become united and extended, (Jigs. 25, 26,) and gradually lose by absorption Fig. 25. Fig. 26. d. the branchial arches, and ultimately form a broad disc, the body of the os hyoides, the anterior margin of which on each side is di- lated into a scutiform process, and the posterior margin bears two bony appendages, which are, in fact, the posterior cornua of that bone. Such are the changes wh
. The cyclopædia of anatomy and physiology. Anatomy; Physiology; Zoology. AMPHIBIA. 99 attached to the cranium ; (jig. 25, a,) the single piece (/>,) and the two rhomboidal pieces (r, r,) in the meantime become united and extended, (Jigs. 25, 26,) and gradually lose by absorption Fig. 25. Fig. 26. d. the branchial arches, and ultimately form a broad disc, the body of the os hyoides, the anterior margin of which on each side is di- lated into a scutiform process, and the posterior margin bears two bony appendages, which are, in fact, the posterior cornua of that bone. Such are the changes which this bone un- dergoes during the gradual passage of the amphibious animal from the tadpole state, in which it represents the class of fishes, to its perfect or reptile condition; and it affords a most interesting instance of the manner in which the true nature of an organ, existing under ambiguous circumstances in one class of animals, is often clearly illustrated by its cha- racters, or, as in the present instance, by its transformations, in another. The minute filiform branchiae, which are appended to the tadpole of the frog im- mediately behind the head, have essentially the same structure as is observed in the gills of the perennibranchiate family, as the siren and the proteus, though in a different form. In the proteus each branchia consists of three principal divisions or branches, from each of which proceed seven or eight leaves, again sub- divided into numerous regular leaflets form- ing the ultimate divisions of the branchiae, on which the extreme capillary branches of the vessels ramify, and in which the blood under- goes its necessary change. A minute rami- fication of the branchial artery, conveying the impure blood from the heart, enters each leaf- let at its base, (Jig. 27, a.) and passes, along Fig. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of th
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