SEXUAL HORMONES AND MORPHOGENESIS 457 



organs of the opposite sex are to be found in every individual 

 {Fig, 137). Rudiments of the Miillerian duct, which develops 

 in the female into the uterus and oviduct, are represented also 

 in the male individual by the appendix testis and the utriculus 

 prostaticus ; rudiments of the Wolffian duct from which the vas 

 deferens in the male originates are represented in the female 

 by the appendix vesiculosa and the longitudinal part of the 

 epoophoron. 



(2) Many cases of intersexuality, where a change into the 

 opposite sex took place during extrauterine life, seem also to 

 support this suggestion, more especially the cock-feathering 

 of old hens. 



(3) A further proof seemed to be supplied by the fact that 

 female sex characters present only in the stock of the father 



W M I M W 



Fig. 137. — Diagram : Origin of the different parts of the male and female sex 

 apparatus. - — ■ — parts normally always present in extrauterine life; 



parts not always present in normal individuals; parts 



present only during intrauterine life. Ov = ovary; T = testis; M = Miil- 

 lerian duct; W = Wolffian duct; Ep = epoophoron or epididymis; P 

 = paroophoron or paradidymis; Av= appendix vesiculosa; Ae= appendix 

 epididymidis; At = appendix testis. — Combination from Bromann and 

 Toldt. 



can be transmitted by the male, and vice versa male characters 

 can be transmitted by the female. An example may be given 

 from an experiment of Mrs. Haig Thomas (1912). A female 

 Formosan pheasant {P.formosus) was mated with a male of the 

 Japanese species (P. versicolor). "The first-cross offspring 

 already showed that each sex can transmit the secondary sexual 

 characters of the other, for the males had some of the characters 

 of the male formosus, the females some of those of the female 

 versicolor. The transference of the female characters by the 

 male was still more clearly proved in the second generation; one 

 of the hybrid females was mated back with the versicolor male, 

 and all the female young produced (five) had all the typical 

 characters of pure versicolor females. In this case there was no 



