1871.] 187 [Wilder. 



step toward this is to recognize that morphically, as shown upon the 

 diagram, these two regions are to each other, as are the right and 

 left sides. 



Hypsetropy. 



Sexual homology, Wild., 58, Lect. 1. — Dual homology. Wild., 58, 

 Lect. 1. 



Definition. The antitropical relation between parts of the two 

 sexes, when facing each other. 



Example. The male and female mammary glands; sterna, etc. 



Remark. This kind of homology often but not necessarily in- 

 cludes the idea of inserted development; the difference between it 

 and the apparent dorso-abdominal homology within a single individual 

 has been already indicated, [p. 183]. 



Meketropy. 



Symmetry in length, Ok., 285, 2114. — Anterior and posterior symme- 

 try, Wy., 35, 317. — Fore and hind symmetry, Wy., 49, 176. — Antero- 

 posterior symmetry, Wy., 55, 277. — Fore and aft polarity, Dana, 218, 

 351. — Antero-posterior polarity, Dana, 218, 351. — Cephality, (?), Ag., 

 ("Rem. on), 298. — Longitudinal homology ', Wild., 45, 14. — Longitypy, 

 Wild., 45, 15. — Anterior and posterior repetition, Wild., 45, 17. — 

 Longitudinal polarity, Wild., 50, 194. — Longitudinal symmetry, Coues, 

 70, 149. — Longitudinal antitypy, Coues, 70, 151. — Symmetry at oppo- 

 site ends, Ogilvie, 283, 156. — Longitropy, Wild., 74, fere. — Symmetry 

 of superior and inferior regions, Gerdy, 9, (?). — Homologie symmet- 

 rique du meme cote', Foltz, 39, 420. — Homotypy (implied in homotype), 

 Wy.,55,/ere. 



Definition. The morphotropical relation between parts upon 

 opposite sides of a vertical lateral plane. 



Example. The cephalic and caudal regions of an embryo; the 

 armus and skelos; a double-ended ferry-boat offers a familiar example 

 of meketropy. 



Remark. Yague suggestions of a polar or symmetrical relation 

 between the anterior and posterior regions of the vertebrate body are 

 contained in the writings of Oken. "The idea underlying his 

 statement that the two ends of the body do repeat each other, is we 

 believe, correct;" Wyman, 55, 257. Duges (Traite de Phys. Comp. 



