PLATE XLVII 



Fig. 1. — Type I double-yolked egg, showing two yolks with separate vitelline mem- 

 branes but inclosed in a common chalaziferous layer. The yolks were slightly pressed 

 apart before photographing, in order to show that the vitelline membranes were 

 entirely separate. 



Fig. 2. — Type II double-yolked egg, showing two yolks with separate chalazal mem- 

 branes but common thick albumen. 



