GEGENBAUR

gegenbaur, carl (1826-1903), german anatomist, was born on the 21st of august 1826 at wurzburg, the university of which he entered as a student in 1845. after taking his degree in 1851 he spent some time in travelling in italy and sicily, before returning to wurzburg as _privatdocent_ in 1854. in 1855 he was appointed extraordinary professor of anatomy at jena, where after 1865 his fellow-worker, ernst haeckel, was professor of zoology, and in 1858 he became the ordinary professor. in 1873 he was appointed to heidelberg, where he was professor of anatomy and director of the anatomical institute until his retirement in 1901. he died at heidelberg on the 14th of june 1903. the work by which perhaps he is best known is his _grundriss der vergleichenden anatomie_ (leipzig, 1874; 2nd edition, 1878). this was translated into english by w.f. jeffrey bell (_elements of comparative anatomy_, 1878), with additions by e. ray lankester. while recognizing the importance of comparative embryology in the study of descent, gegenbaur laid stress on the higher value of comparative anatomy as the basis of the study of homologies, i.e. of the relations between corresponding parts in different animals, as, for example, the arm of man, the foreleg of the horse and the wing of a fowl. a distinctive piece of work was effected by him in 1871 in supplementing the evidence adduced by huxley in refutation of the theory of the origin of the skull from expanded vertebrae, which, formulated independently by goethe and oken, had been championed by owen. huxley demonstrated that the skull is built up of cartilaginous pieces; gegenbaur showed that "in the lowest (gristly) fishes, where hints of the original vertebrae might be most expected, the skull is an unsegmented gristly brain-box, and that in higher forms the vertebral nature of the skull cannot be maintained, since many of the bones, notably those along the top of the skull, arise in the skin." other publications by gegenbaur include a _text-book of human anatomy_ (leipzig, 1883, new ed. 1903), the _epiglottis_ (1892) and _comparative anatomy of the vertebrates in relation to the invertebrates_ (leipzig, 2 vols., 1898-1901). in 1875 he founded the _morphologisches jahrbuch_, which he edited for many years. in 1901 he published a short autobiography under the title _erlebtes und erstrebtes_. see furbringer in _heidelberger professoren aus dem 19ten jahrhundert_ (heidelberg, 1903). gegenschein (ger. _gegen_, opposite, and _schein_, shine), an extremely faint luminescence of the sky, seen opposite the direction of the sun. germany was the country in which it was first discovered and described. the english rendering "counterglow" is also given to it. its faintness is such that it can be seen only by a practised eye under favourable conditions. it is invisible during the greater part of june, july, december and january, owing to its being then blotted out by the superior light of the milky way. it is also invisible during moonlight and near the horizon, and the neighbourhood of a bright star or planet may interfere with its recognition. when none of these unfavourable conditions supervene it may be seen at nearly any time when the air is clear and the depression of the sun below the horizon more than 20°. (see zodiacal light.)