And all these are remarkable evidences of an increased adaptation to water life in the more recent ichthyosaurs over the older ones. Were someone now so fortunate as to find ichthyosaurs in late Permian rocks, we should doubtless have the nearly complete chain between the most highly specialized type of water reptiles and their terrestrial ancestors. [Illustration: FIG. 58.—Caudal fin of _Ichthyosaurus_, after Baur (left figure); caudal fin of _Mixosaurus_, after Wiman (right figure).] From the structure of the skeleton alone the early observers were justified in inferring much concerning the shape and habits of the living ichthyosaurs. Later discoveries have added so many definite facts that, at the present time, we know more about their habits than we do of any other extinct reptiles. In various places in England and Germany, especially in Würtemberg, the remains of ichthyosaurs are found in extraordinary abundance and perfection, not only whole skeletons lying in the positions which they had assumed after the decomposition of their bodies, but also often the actual remains, carbonized, of the skin, muscles, and ligaments, as well as delicate impressions of external parts. Many of these skeletons are obtained from the numerous stone quarries, where they are a sort of “by-product,” the sums received for them adding not a little to the income of the quarrymen. So many are obtained in this and other ways that specimens of ichthyosaurs are perhaps more frequently seen in the museums of the world than those of any other extinct backboned animal. Fairly complete skeletons may now be purchased of dealers in such things for from fifty to seventy-five dollars. As may be supposed, the best and most complete collections of these fossil remains are those of the British Museum in London and the museum in Stuttgart. From a study of those of the last-mentioned museum Professor Fraas has learned many interesting facts and reached many interesting conclusions regarding the life-habits of the ichthyosaurs. In the accompanying figure (Fig. 59) is shown a photographic reproduction of a very complete specimen, in which not only is the outline of the whole body shown, but also much of the carbonized remains of the muscles and skin has been detected. [Illustration: FIG. 59.—_Ichthyosaurus quadricissus._ (From a photograph from B. Hauff, Paleontologisches Atelier, Holzmaden.)] The attachment of the paddles to the body was broad antero-posteriorly, proving conclusively that they could not have been much used in propulsion, either in the water or upon land, since such use would require a fore-and-aft movement, and a consequent twisting or rotation of the whole arm or leg, which, because of the broad attachment, must have been very difficult, if not impossible.