212 Secondary Male Characten^ in a PJieamnt 



pattern, the bird at that time showing the full adult male plumage and 

 functioning as a male. 



It is I think reasonable to conclude that the gametic factors (what- 

 ever their nature) in this case controlled the pigmentary pattern of this 

 tail feather alternately along male and female lines, whereas in my 

 hermaphrodite specimen they controlled the pigmentary pattern in 

 opposite halves of each tail feather coincidently. 



But there is yet another point of interest about the tail. 



In the Royal College of Surgeons Museum the skin and the internal 

 organs are preserved of a true hermaphrodite Leghorn fowl. The micro- 

 scopic structure of the double sex gland in this case has been carefully 

 worked out by Shattock; it undoubtedly constitutes an ovo-testis. In this 

 specimen a well-developed male comb and spurs are present, but there 

 are no sickle feathers and the tail as a whole (though rather long) is of 

 the female type. The distribution of the male sex characters is arranged 

 on an antero-posterior or segmental rather than a bilateral pattern. 



There would seem then to be two main types of sex character 

 manifestation, as far as the body and limbs are concerned. 



Type I. In which a double sex gland is associated with a hemi- 

 lateral distribution of secondary sex characters, as in my specimen. 



Type II. In which a double sex gland is associated with an antero- 

 posterior or transverse distribution of secondary sex characters, as in 

 this White Leghorn fowl. These two Types might be distinguished as 

 the Lateral and the Segmental Types. 



Although both halves of the tail seem to function in heredity as one 

 whole (no one has seen a tail with one half male and the other half 

 female), yet the individual tail feathers show the same antero-posterior 

 and hemilateral types of manifestation of secondary sex characters that 

 we find in the body as a whole. 



The first type is illustrated by the hemilateral male and female 

 pigmentary pattern in each feather in my hermaphrodite specimen. 

 The second type is illustrated by the transverse distribution of the 

 same characters in the tail feathers in Shattock's specimen (cf. PL XI, 

 fig. 14). Both represent extreme conditions of the normal arrangement 

 in the tails of many birds in which not only does the outer or less 

 covered side of the tail feathers exhibit a different pigmentary pattern 

 to the inner side, but the distal portion may be also marked off from 

 the proximal portion by transverse areas of different pattern. 



The value of this specimen seems to lie in the light it may possibly 

 throw on the process of Sex Differentiation. This individual bird shows 



