i 9 8 



POPULAR SCIENCE MONTHLY. 



hypophylangia (two-jointed instead of three-jointed digits) is dominant 

 over the normal condition. In mice, the peculiar waltzing habit of so- 



Fig. 6. A Guinea-pig with Short, Pigmented Coat. Its parents were the animal shown in 



Fig. 4 and one like that shown in Fig. 5. 



Fig. 7. A Guinea-pig with Long, Smooth, Albino Coat. These three characters 



are all recessive in nature. 



called Japanese mice is a recessive character in heredity. In man, a 

 peculiar dark-colored condition of the urine, known as alkaptonuria, is 



