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Rh curved backwards: one lung is larger than the other.

In these particulars there is a greater or less degree of affinity to the Ophidian forms, and perhaps more particularly to those which present the evanescent characters of the lowest Saurians, as Anguis and Typhlops. It must be observed that the two branches of the lower jaw are firmly soldered together in front, and that they are jointed behind immediately on the skull, without the intervention of a bony foot-stalk, in both which particulars they vary from the true Serpents.

But there are characters of more importance which demand the arrangement of these animals among the Amphibia, notwithstanding all these affinities with a higher type. The first of these is the articulation of the skull to the first vertebra of the spine, by means of two separate and well marked projections (condyles),—a strongly distinctive mark of this Sub-class; secondly, the vertebræ are hollowed in front and in rear into conical excavations; and (what is decisive, if it may be depended on) the presence of branchiæ, involving a metamorphosis, is said to have been detected in the young. Müller announced the discovery of branchial apertures in a young Cæcilia hypocyanea preserved in the Museum of Natural History at Leyden. He noticed an orifice a line in width on each side of the neck, some distance behind the gape, situated in the yellow stripe which runs down the side, and communicating freely with the mouth. The edge of the hole was rough, and in the interior he observed black fringes, which appeared to