CASTLE 



PLATE 1 



1. A Young Black Guinea-Pig, about three weeks old. Ovaries taken from two 



animals like this were transplanted into the albino shown in Fig. 2. 



2. An Albino Female Guinea-Pig, No. 27. Its ovaries were removed and in their place 



were introduced ovaries from two young black guinea-pigs. Compare Fig. I. 



3. An Albino Male Guinea-Pig, No. 654, with which was mated the albino shown 



in Fig. 2. 



