HOMOLOGY

(Yunanca köken — orijinale bakınız.) In Anatomy, that department of the scien its organisation. Thus, firstly, the wing of a bird is, hi mologically, the same limb as the arm of a man or tl fore-foot of ahorse: and the "os quadratum " of bird is shown to be the same bone as the "os tyn panicum " of the tortoise, and as the " auditory pri ce of the temporal bone" of a man. They a said to be "homologous" parts, and the propositioi are examples of what has been called " special hom logy." Secondly, the wing of a bir,d is the same correlative part in its segment of the body, as the leg in a more posterior segment: just as the frontal bone the correlative element in its segment, with the sup< occipital bone in its segment. The wing of the rig side is also the answerable part of the wing of the side; in the same way that the right neurapophysis any given segment answers to the left neurapophysis the same segment. Propositions of this kind are amples of what is termed " serial homology; " and parts so corresponding are said to be " homotypal thus the arm is the homotype of the leg, the humer of the femur, the radius of the tibia, the ulna of fibula, . Thirdly, in relation to the archetype of 1 vertebrate skeleton, the arm is the "diverging appen age " of its segment; the super occipital bone is the " ne ral spine;" the exoccipital bone or " condyloid part the occipital bone" in " Anthropotomy" is the "net apophysis; " the bas i occipital bone or " basilar proce the occipital bone " is the " centrum " or " body " of segment: these proposition^ are instances of what termed " general homology," as being expre ive oft highest generalisations in that philosophical departm< of anatomical science. — See Owen On the Archety and Homologies of the Vertebrate Skeleton. [s. 1391]