ORDER III. AMPHIPNEUSTA.
(Doubly-breathing Reptiles.)
In these animals the body is much lengthened, and adapted for swimming; the limbs are small, feeble, and far removed from each other, and in some species the hind pair are wanting. The tail is compressed, and remains through life. The respiration is performed in a two-fold manner, in water by means of gills, which are external, and continue throughout the whole term of existence, and in air, by means of lungs, likewise permanent. The eyes are furnished with eyelids.
The term Amphibia, having reference to the two-fold medium and manner in which is carried on the most important function of life, the renewing of the vitality of the blood, is with literal strictness applicable to these singular forms: for it is descriptive, not of a preparatory and rudimentary condition of existence, but of that which, subsisting through life, is truly proper to the animal. “The simultaneous existence and action of branchial tufts and lungs in these animals,” observes Cuvier, “can no more be contested than the most certain facts of natural history; I have before me the lungs of a Siren of three feet in length, where the vascular apparatus is as much developed and as complicated as in any reptile: nevertheless this Siren had its branchiæ
