142 



THE BIOLOGY OF TWINS 



fetus III the doubling involves the whole band, for 

 there is an extra or tenth band present; in fetus I the 

 whole band is double except four scutes on the left 



Fig. 44. — A detail drawing of band and scute doubling in set K 4 



margin; and in fetus IV the whole is double except four 

 scutes on the left and five on the right. Fetuses I 

 and II (a pair) are aUke in being unilateral in doubling, 



