Christian Gottfried Eherenberg, a German naturalist, born at Delitzsch, April 19, 1795. He was educated at Leipsic and Berlin. In 1818 he published Sylvoe Mycologicoe Beroli-nenses, in which he described 62 new species of cryptogamous plants. In 1820 he visited Egypt, Nubia, and Arabia, at the expense of the Berlin academy of sciences, and continued his scientific explorations in those countries for six years. On his return to Berlin he was appointed extraordinary professor of medicine. In 1829 he accompanied Humboldt to the Ural mountains and central Asia. In 1842 he was elected permanent secretary of the academy, and in 1847 was appointed to a regular professorship. The scientific results of his observations in Africa are contained in Symboloe physical Mammalium, Avium, Insectorum et Animalium Evertebratorum (Berlin, 1828-'33); Die Korallenthiere des Rothen Meeres (1834); and Die Akalephen des Rothen Meeres (1836). He engaged in the investigation of infusoria, and arrived at results of the greatest value, which were presented in various publications, the most complete of which is Die Jnfusions-thierchen als vollkommene Organismen (with 64 plates, Leipsic, 1838). He discovered fossil infusoria, showed the similarity of their phenomena in different parts of the world, and published on this subject Die fossilen Infuso-rien und die lebendige Dammerde (1837); Die Bildung des europdischen, libyschen und ura-lischen Kreidefelsens und Kreidemergels aus mikroskopischen Organismen (1839); and especially Mikrogeologie (1854). For some account of his discoveries and classification, see Animalcules. Among his works on other subjects is Ueber die naturwissenschaftlich und medicinisch vollig unbegrundete Furclit vor lcorperlicher Entkraftung der Volker durch die fortschreitende Geistesentwickelung (Berlin, 1842). His latest publication is Mikrogeo-logische Studien als Zusammen fassung seiner Beobachtungen des kleinsten Lebens der Mee-restiefgrunde aller Zonen und uber dessen geo-logischen Einfluss (Berlin, 1872).