Vol. XXVI. February, 7914. No. 2 



BIOLOGICAL BULLETIN 



STUDIES ON THE PHYSIOLOGY OF REPRODUCTION 

 IN THE DOMESTIC FOWL. 



VI. DOUBLE- AND TRIPLE-YOLKED Eccs. 1 



MAYNIE R. CURTIS. 



The most common type of abnormal egg produced by the 

 domestic fowl is the double-yolked egg. Eggs with three yolks, 

 however, are very rare. The purpose of the present paper is, 

 first, to record some observations on the frequency of the occur- 

 rence of double- and triple-yolked eggs and the relation of their 

 production to the age of the bird; and, second, to consider so far 

 as possible the nature of the processes involved in their formation 

 and the contribution that such a study makes to our knowledge 

 of the physiology of egg production. 



THE FREQUENCY OF OCCURRENCE OF DOUBLE- AND TRIPLE- 

 YOLKED EGGS AND THE RELATION OF THEIR PRODUCTION 



TO THE AGE OF THE BlRD. 

 During the last six years only three triple-yolked eggs are 



known to have been produced by the flock of birds belonging to 



1 Papers from the Biological Laboratory of the Maine Agricultural Experiment 

 Station, No. 56. 



The previous papers in the series of "Studies on the Physiology of Reproduction 

 in the Domestic Fowl " are: 



I. Pearl, R., "Regulation in the Morphogenetic Activity of the Oviduct," 

 Jour. Exp. ZooL, Vol. 6, pp. 339-359, 1909. 



II. Pearl, R., and Surface, F. M., "Data on the Inheritance of Fecundity 

 Obtained from the Records of Egg Production of the Daughters of 2oo-egg Hens," 

 Me. Agr. Exp. Sta. Ann. Rept., 1909, pp. 49-84. 



. III. Pearl, R., and Curtis, M. R., "A Case of Incomplete Hermaphroditism," 

 BIOL. BULL., Vol. 17, pp. 271-286, 1909. 



IV. Pearl, R., and Surface, F. M., "Data on Certain Factors Influencing the 

 Fertility and Hatching of Eggs," Me. Agr. Exp. Sta. Ann. Rept., 1909, pp. 105-164. 



V. Pearl, R., and Curtis, M. R., "Data Regarding the Physiology of the Ovi- 

 duct," Jour. Exp. ZooL, Vol. 12, pp. 99-132. 



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