138 



THE BIOLOGY OF TWINS 



All four fetuses have a more or less extensive doubling 

 of the same band. In fetuses I, II, and IV the doubling 

 is bilateral, but the more extensive doubling is on the 



Fig. 42. — A detail drawing of all the bands that show doubling in 

 mother and offspring of set K 87. if = mother; I, II, III, IV, the four 

 fetuses. 



