PHYSIOLOGY OF REPRODUCTION IX DOMESTIC FOWL. 7 1 



TRIPLE-YOLKED EGGS. 



The same processes which cause the formation of double- 

 yolked eggs may also cause the formation of triple-yolked eggs. 

 The number of triple-yolked eggs, however, is so small that an 

 extensive study of them is impobsible. The first of the triple- 

 yolked eggs produced by the station flock was fully described by 

 Dr. Raymond Pearl. 1 He called attention to the size relation 

 between this egg and double-yolked, single-yolked and yolkless 

 eggs of the same breed (Barred Plymouth Rock), and showed 

 that the parabola 



W = 16.242 + 43.7627 - 4.450 Y 2 

 gave an extremely close fit. to the observations. 



FIG. 2. Triple-yolked egg. 



He describes the internal characters of the egg as follows: 

 "Each yolk was enclosed in a separate yolk membrane. While 

 the three yolks were in contact with each othei, they were in no 



i Pearl, R., "A Triple- Yolked Egg," Zool. Anz., Bd. XXXV., pp. 418-423. 



