240 THE AMERICAN NATURALIST [Vol. LIV 



female, including especially the genitalia. They have 

 rudimentary gonads. Breeding from normal heterozy- 

 gous sisters and brothers he has shown that there is 

 present a recessive gene that gives the intersexes when 

 present in double dose in females. This gene is in an 

 autosome. The results are shown, therefore, not to be 

 due to a change in the gene or genes for sex, but to a gene 

 whose effects are superimposed on the influence of the 

 sex genes. It is evident that such a possibility must be 

 reckoned with in interpreting other cases. 



Intersexes have been found in human lice, Pediculus, 

 by Keblin and Nuttall. The evidence makes it probable 

 that these arise most frequently when the body louse, P. 

 corporis, crosses with the head louse P. capitis. These 

 intersexes have both male and female gonads and geni- 

 talia in the same individual, differently combined. 



It has long been known that crosses between Gallina- 

 ceous birds give rise to males that are sterile although 

 such males are not described as intersexes. Whether 

 only the male hybrids survive or whether the female hy- 

 brids are sometimes turned into males is not known. 

 Guyer has raised the question as to whether the individ- 

 uals in question if ever females might be classified as 

 males, because of the rudimentary condition of the ovary. 

 It is well known to-day that removal of the ovary of the 

 hen causes her to assume the male plumage (Goodale), 

 and also it is more than suspected that tumors in the 

 ovary or other diseases of that organ produce a like 

 effect on the plumage. But Guyer points out that in the 

 few cases examined by him testes were present. Biddle 

 has described many cases in hybrid doves in which the 

 sexual behavior of certain individuals showed them to 

 have opposite sex tendencies from that indicated by their 

 gonads. These he calls sex intergrades. It is well known 

 to poultrymen that birds in poor condition sometimes., 

 behave queerly in their sex relations. It is possible that 

 the weakened condition of these doves may have some- 

 thing to do with their anomalous behavior. But aside 



