PHYSIOLOGY OF REPRODUCTION IX DOMESTIC FOWL. 



67 



FIG. i. Diagrams showing the various relations of the two yolks in double- 

 yolked eggs where the yolks have common albumen envelopes, a, two yolks of a 

 double-yolked egg which have all the envelopes in common; b, the form transitional 

 between a double-yolked egg where the chalazal membrane is common to the two 

 yolks and where each has a separate chalazal membrane; c, d, e and /, showing 

 arrangements of the two yolks which have been observed in double-yolked eggs 

 where the yolks have separate chalazal membranes but common albumen envelopes. 



