| Two views of the tooth of a Glyptodon; the upper figure showing one side, and the lower the crown. |
Glyptodonts constitute a family, the Glyptodontidae, whose position is next to the armadillos (Dasypodidae); the group being represented by a number of generic types. The Pleistocene forms, whose remains occur abundantly in the silt of the Buenos Aires pampas, are by far the largest, the skull and tail-sheath in some instances having a length of from 12 to 16 ft. In Glyptodon (with which Schistopleurum is identical) the tail-sheath consists of a series of coronet-like rings, gradually diminishing in diameter from base to tip. Daedicurus, in which the tail-sheath is in the form of a huge solid club, is the largest member of the family, in Panochthus and Sclerocalyptus (Hoplophorus) the tail-sheath consists basally of a small number of smooth rings, and terminally of a tube. In some specimens of these genera the horny shields covering the bony scutes of the carapace have been preserved, and since the foramina, which often pierce the latter, stop short of the former, it is evident that these were for the passage of blood-vessels and not receptacles for bristles. In the early Pleistocene epoch, when South America became connected with North America, some of the glyptodonts found their way into the latter continent. Among these northern forms some from Texas and Florida have been referred to Glyptodon. One large species from Texas has, however, been made the type of a separate genus, under the name of Glyptotherium texanum. In some respects it shows affinity with Panochthus, although in the simple structure of the tail-sheath it recalls the undermentioned Propalaeohoplophorus. All the above are of Pleistocene and perhaps Pliocene age, but in the Santa Cruz beds of Patagonia there occur the two curious genera Propalaeohoplophorus and Peltephilus, the former of which is a primitive and generalized type of glyptodont, while the latter seems to come nearer to the armadillos. Both are represented by species of comparatively small size. In Propalaeohoplophorus the scutes of the carapace, which are less deeply sculptured than in the larger glyptodonts, are arranged in distinct transverse rows, in three of which they partially overlap near the border of the carapace after the fashion of the armadillos. The skull and limb-bones exhibit several features met with in the latter, and the vertebrae of the back are not welded into a continuous tube. There are eight pairs of teeth, the first four of which are simpler than the rest, and may perhaps therefore be regarded as premolars. More remarkable is Peltephilus, on account of the fact that the teeth, which are simple, with a chevron-shaped section, form a continuous series from the front of the jaw backwards, the number of pairs being seven. Accordingly, a modification of the character, even of the true Edentata, as given in the earlier article, is rendered necessary. The head bears a pair of horn-like scutes, and the scutes of the carapace and tail, which are loosely opposed or slightly overlapping, form a number of transverse rows.
Literature.—R. Lydekker, “The Extinct Edentates of Argentina,” An. Mus. La Plata—Pal. Argent. vol. iii. p. 2 (1904); H. F. Osborn, “‘Glyptotherium texanum,’ a Glyptodont from the Lower Pleistocene of Texas,” Bull. Amer. Mus., vol. xvii. p. 491 (1903); W. B. Scott, “Mammalia of the Santa Cruz Beds—Edentata,” Rep. Princeton Exped. to Patagonia, vol. v. (1903-1904).
(R. L.*)
GLYPTOTHEK (from Gr. γλυπτός, carved, and θήκη, a place of storage), an architectural term given to a gallery for the exhibition of sculpture, and first employed at Munich, where it was built to exhibit the sculptures from the temple of Aegina.
GMELIN, the name of several distinguished German scientists, of a Tübingen family. Johann Georg Gmelin (1674-1728), an apothecary in Tübingen, and an accomplished chemist for the times in which he lived, had three sons. The first, Johann Conrad (1702-1759), was an apothecary and surgeon in Tübingen. The second, Johann Georg (1709-1755), was appointed professor of chemistry and natural history in St Petersburg in 1731, and from 1733 to 1743 was engaged in travelling through Siberia. The fruits of his journey were Flora Sibirica (4 vols., 1749-1750) and Reisen durch Sibirien (4 vols., 1753). He ended his days as professor of medicine at Tübingen, a post to which he was appointed in 1749. The third son, Philipp Friedrich (1721-1768), was extraordinary professor of medicine at Tübingen in 1750, and in 1755 became ordinary professor of botany and chemistry. In the second generation Samuel Gottlieb (1743-1774), the son of Johann Conrad, was appointed professor of natural history at St Petersburg in 1766, and in the following year started on a journey through south Russia and the regions round the Caspian Sea. On his way back he was captured by Usmey Khan, of the Kaitak tribe, and died from the ill-treatment he suffered, on the 27th of July 1774. One of his nephews, Ferdinand Gottlob von Gmelin (1782-1848), became professor of medicine and natural history at Tübingen in 1805, and another, Christian Gottlob (1792-1860), who in 1828 was one of the first to devise a process for the artificial manufacture of ultramarine, was professor of chemistry and pharmacy in the same university. In the youngest branch of the family, Philipp Friedrich had a son, Johann Friedrich (1748-1804), who was appointed professor of medicine in Tübingen in 1772, and in 1775 accepted the chair of medicine and chemistry at Göttingen. In 1788 he published the 13th edition of Linnaeus’ Systema Naturae with many additions and alterations. His son Leopold (1788-1853), was the best-known member of the family. He studied medicine and chemistry at Göttingen, Tübingen and Vienna, and in 1813 began to lecture on chemistry at Heidelberg, where in 1814 he was appointed extraordinary, and in 1817 ordinary, professor of chemistry and medicine. He was the discoverer of potassium ferricyanide (1822), and wrote the Handbuch der Chemie (1st ed. 1817-1819, 4th ed. 1843-1855), an important work in its day, which was translated into English for the Cavendish Society by H. Watts (1815-1884) in 1848-1859. He resigned his chair in 1852, and died on the 13th of April in the following year at Heidelberg.