208 Secondary Male Characters in a Pheasant 



(c) Although the complete removal of the sex glands at an early 

 age in the male does no doubt prevent the development of secondary 

 male characters in most vertebrates, it does not produce the develop- 

 ment of female secondary characters except in so far as these resemble 

 those of the young or immature male. 



In the few recorded cases (chiefly among birds) where males have 

 taken on female plumage, either completely or in part, the change has 

 accompanied some (at present unknown) natural cause independently 

 of castration and unassociated in most cases with any atrophic change 

 in the testes (Hammond Smith, The Field, Feb. 25, 1911). It is 

 possible therefore that the assumption of female plumage may be 

 associated with the growth of some dormant ovarian elements in some 

 abnormal situation. In any case the more frequent occurrence of the 

 change in the female is of interest when we recall the supposed hetero- 

 zygous constitution of the female in respect of sex. 



Influenced by these facts Geoffrey Smith and Mrs Haig Thomas 

 (Journ. Genetics, June 1913) suggest a different causation for the 

 secondary sex characters in each case. They suggest that the case 

 of the female assuming the characters of the male sex is one of 

 "Correlated Differentiation" and is directly associated with changes 

 in the corresponding sex gland, while the . case of the male assuming 

 female characters is due to the " Hereditary Transference " of characters 

 originally associated with one sex to individuals of the opposite sex, and 

 they instance the hen plumage of the Sebright Bantam Cock as a case 

 in point. 



But even supposing it to be tru,e, as seems likely, that the case 

 of the female assuming male characters and the case of the male 

 assuming female characters rest on a different footing as regards 

 causation, this specimen still falls into a different category be- 

 cause the assumption of the opposite sex character is limited to 

 one side of the body in this individual. While it seems clear that 

 such a localized change of plumage cannot be entirely dependent on 

 the circulation in the blood of any internal secretion it is also clear that 

 the explanation of opposite sex characters by Hereditary Transference 

 is also insufficient, because in this individual bird the sex characters are 

 different on the two sides of the body. Moreover, not only are the 

 somatic characters different on the two sides but the sex gland is also 

 a dual gland composed of male and female elements. The bird is in 

 fact a true genetic as well as a somatic Hermaphrodite. It should 

 I think be placed in a separate class along with those described by 



