HOMOLOGUE 



573 



HOMOTHERMOUS 



Homologue (hom'-o-Iog) [o/ioc, same; '/oyoq, propor- 

 tion]. An homologous organ common to any number 

 of species, classes, or orders of animals ; that which 

 has the same relative structure, position, or develop- 

 ment as another. The same organ in different organ- 

 isms under every variety of form and function. We may 

 have: I. Homogenetic Homologues, i.e., parts 

 which, on the evolutionary theory, have a genetic rela- 

 tion, e. g. , the humerus of a horse and that of an ox. 

 2. Homoplastic Homologues, i. e., parts closely 

 similar as to relative position, but with no genetic af- 

 finity, or only a remote one, e. g. , the ventricle of a bat 

 and that of a bird. 3. Homogenetic Serial Homo- 

 logues, i.e., different parts of one individual, the 

 correspondence between which is to be accounted for 

 by the influence of external conditions (the " superin- 

 duced segmentation" of Mr. Herbert Spencer), e.g., 

 the fore-limbs and hind-limbs of one side of any animal. 

 4. Vertical Homologues, i. <?., different correspond- 

 ing parts of one individual, of which one part is dorsal, 

 the other ventral, e.g., dorsal and anal fins of certain 

 fishes. 5. Lateral Homologues, i. e., different cor- 

 responding parts of one individual, of which one part 

 is right and the other left, e. g. , the right and left arms 

 of a man. 6. Antero-posterior Homologues, i. e., 

 different corresponding parts of one individual, of 

 which one part is anterior, the other posterior, e.g., 

 the mouth and the cloaca. 7. Radial Homologues, 

 i. e., different corresponding parts of one individual 

 which radiate from a central axis, e. g. , any two arms 

 on the same starfish. 8. Homotrophic Homologues, 

 i. e., parts of an individual, the correspondences be- 

 tween which are regarded as due to internal modifying 

 influences, e.g., the eyes and the ears. 9. Actinol- 

 ogous Homologues, i. e. , successive subdivisions, 

 parts, or regions of a part or segmented organ, e.g., 

 two successive joints of an antenna of a lobster, or 

 the vertebral and sternal parts of the same costal ele- 

 ment. 10. Special Homologues, i. e., parts of two 

 organisms belonging to the same special skeletal cate- 

 gory, e.g. . the basi-occipital of man and the cod. II. 

 General Homologues, i. e. , parts of two organisms 

 belonging to the same general skeletal category, e.g., 

 the vertebral center of man and that of the cod, or the 

 lateral appendages of the lobster and those of the scor- 

 pion. (Mivart.) 



Homology (ho-mol' -o-je) \bpAq, same ; Aoyoc, proportion]. 

 The quality of being homologous ; also, the morpho- 

 logic identity of parts or organs in different animals. 

 In biology, a term introduced by R. Owen to indicate 

 a close resemblance between parts, depending upon 

 relations of relative position. (Mivart.) 



Homomalous (ho-mom' -al-us) \b(ia'tx>q, even, level, 

 equal]. In biology, applied to parts or organs that 

 are all turned to one side. 



Homomorphism (ko-mo-mor / -Jizm) [ouoc, the same ; 

 popoi), form]. In biology, superficial resemblance, 

 without true homology ; mimicry or adaptive resem- 

 blance. 



Homomorphous (ho-mo-mor* -fus) [6ti6q, the same ; 

 (lopoij, form]. In biology, exhibiting superficial 

 resemblance, but not truly homologous. 



Homonomous (ho-mon* -o-mus) [6u6c, same ; vouoc, 

 law]. Governed by or under the same law. 



Homonym (Aom'-o-nim) [6/160, same ; btrofia, name]. 

 That which is homonymous. 



Homonymous (ho-mon' '-im-us) \0u6q, same ; bwua, 



I a name]. I. A term applied to names that have the 

 same sound or pronounciation, but different meanings. 

 2. Coming under the same general designation 

 (thus the two external recti muscles are homony- 



of the body ; not heteronomous. H. Diplopia, 

 occurs when the image seen by the right eye seems to 

 be on the right side and that seen by the left eye seems 

 to be on the left side. H. Hemianopia, occurs when 

 all points in the visual field of each eye lying to the 

 right (Right H. H.) or to the left (LeftH. H.) of 

 the fixation-point are not seen. 



Homophthalic Acid (ham-off -thai' -ik). See Acid. 



Homophthalimid (hom-off-thal'-im-id) [ouoc, same; 

 wjfla/jioc , eye ; imid\ , CgH.NOj. A substance produced 

 when the ammonium salt of homophthalic acid is 

 heated. It crystallizes in minute needles, melting at 

 233° C. 



Homophyadic (ho-mo-fi-ad' -ik) \ofioq, the same ; 

 (pieatlai, to grow]. In biology, having but one kind 

 of stem, as distinguished from heterophyadic. 



Homophyly (ho-moff 7 -il-e) [6uoc, the same ; $v?j?, 

 race]. In biology, correspondence in genetic rela- 

 tionships. 



Homoplasis (ho-mo-pla' -sis) [o««5c, the same ; v?moic, 

 formed]. In biology, Lankester's term for structural 

 agreement or modification resulting from the action of 

 identical or nearly similar forces or environments on 

 two or more parts of an organism, or on two organisms, 

 which parts are exactly or nearly alike, or perhaps 

 homogenetic. The same as the " superinduced seg- 

 mentation " of Spencer. 



Homoplasmic (ho-mo-plaz' '-mik). Same as .Homo- 

 plastic. 



Homoplasmy (ho r -mo-plaz-me) [ou<5c, the same ; 

 Tz'/.aoua, a thing moulded]. In biology, homoplastic 

 or homomorphic, i. e. , showing mimetic resemblances. 



Homoplast (ho 1 '-mo-plast) \ouoq, the same ; ~7.aar6c, 

 formed, moulded]. In biology; 1. One of any aggregate 

 or fusion of plastids. 2. An organ or part showing mere 

 superficial or mimetic resemblance to another. 



Homoplastic (ho-mo-plas / -tik) \0p6c, the same ; -'/mot6\, 

 formed]. In biology, showing close agreement, de- 

 pendent upon the common action of evoking causes 

 or moulding environment upon homogeneous parts, or 

 on parts that, for other reasons, offer a likeness of 

 material to begin with. (Lankester.) 



Homoplasy (ho* ' -mo-plaz-e) [ouoc, the same ; iz/.aaiq, a 

 forming, moulding]. In biology, agreement in the 

 form, structure, and perhaps function, of organs or 

 parts in the same or separate organisms, dependent 

 upon evoking causes other than genetic affinity. 



Homopterous (ho-mop* -ter-us) [ouoc, the same ; ~ep6v, 

 wing, feather]. In biology, applied to insects having 

 wings of the same texture throughout. 



Homorgan (hom f -or-gan) [ouoc, the same ; bpyavov, 

 organ] . In biology, an organ resembling another ; a 

 homoplast. 



Homosexual (ho-mo-seks / -u-al) [o/ioc, same ; sexus, 

 sex]. Pertaining to the same sex. 



Homosexuality (ho-mo-seks-u-aP '-it-e) [6u6g, same ; 

 sexualis, of a sex]. That form of sexual perversion, 

 acquired or congenital, in which the individual con- 

 ceives a violent sexual passion for one of the same 

 sex, and gratifies it either by sodomy, by titillation, or 

 platonically. 



Homosporous (ho-mos* -por-us) {ofidg, similar; oiropog, 

 seed]. In biology, producing but one kind of spores ; 

 isosporous. 



Homostyled (ho f -mo-stild) [6/zoc, the same ; arV/xtq, 

 pillar]. See Homogonous. 



Homothermic (ho-mo-ther* -mik) [6fi6$, same; depun, 

 heat]. Having uniformity of temperature or bodily 

 heat. 



Homothermous (ho-mo-ther* -mus) \0u6q, the same; 

 Okpfttj, heat]. In biology, applied to animals showing 

 the same degree of bodily heat. 



