AFFINITIES AND GENEALOGY. 157 



been hermaphrodite or androgynous.'^" But here we encounter 

 a singular difficulty. In the mammalian class the males possess 

 rudiments of a uterus with the adjacent passage, in their vesiculse 

 prostaticffi; they bear also rudiments of mammae, and some male 

 Marsupials have traces of a marsupial sack.^' Other analogous 

 facts could be added. Are we, then, to suppose that some ex- 

 tremely ancient mammal continued androgynous, after it had 

 acquired the chief distinctions of its class, and therefore after it 

 had diverged from the lower classes of the vertebrate kingdom? 

 This seems very improbable, for we have to look to fishes, the 

 lowest of all the classes, to find any still existent androgynous 

 forms. =' That various accessory parts, proper to each sex, are 

 found in a rudimentary condition in the opposite sex, may be 

 explained by such organs having been gradually acquired by the 

 one sex, and then transmitted in a more or less imperfect state 

 to the other. When we treat of sexual selection, we shall meet 

 with innumerable instances of this fo'rm of transmission, — as in 

 the case of the spurs, plumes, and brilliant colors, acquired for 

 battle or ornament by male birds, and inherited by the females 

 in an Imperfect or rudimentary condition. 



The possession by male mammals of functionally imperfect 

 mammary organs is, in some respects, especially curious. The 

 Monotremata have the proper milk-secreting glands with orifices, 

 but no nipples; and as these animals stand at the very base of 

 the mammalian series, it is probable that the progenitors of 

 the class also had milk-secreting glands, but no nipples. This 

 conclusion is supported by what is known of their manner of 

 development; for Professor Turner informs me, on the authority 



-« This is the conclusion of Prof. Gegenbaur, one of the highest au- 

 thorities in comparative anatomy; see 'Grundzuge der vergleich. 

 Anat.' 1870, o. 876. The result has been arrived at chiefly from the 

 study of the Amphibia; but it appears from the researches of Wal- 

 deyer (as quoted in 'Journal of Anat. and Phys.' 1869, p. 161), that the 

 sexual organs of even "the higher vertebrata are, in their early condi- 

 "tion, hermaphrodite." Similar views have long been held by some 

 authors, though until recently without a firm basis. 



^ The male Thylacinus offers the best instance. Owen, 'Anatomy of 

 Vertebrates," vol. iii. p. 771. 



^ Hermaphroditism has been observed in several species of Serranus, 

 as well as in some other fishes, where it is either normal and sym- 

 metrical, or abnormal and unilateral. Dr. Zouteveen has given me ref- 

 erences on this subject.more especially to a paper by Prof.Halbertsma, 

 in the 'Transact, of the Dutch Acad, of Sciences,' vol. xvi. Dr. Gun- 

 ther doubts the fact, but it has now been recorded by too many good 

 observers to be any longer disputed. Dr. M. Dessona writes to me, 

 that he has verified the observations made by Cavolini on Serranus. 

 Prof. Ercolani has recently shown ('Accad. delle Scienze,' Bologna, 

 Dec. 28, 1871) that eels are androgynous. 



