574 Journal of Agricultural Research voi. xii, N0.9 



SUMMARY 



(i) An examination of the data published by Gowell confirms the 

 statements of Pearl and Surface (7) and Pearl (3,6) regarding the presence 

 of a winter cycle in Barred Plymouth Rocks. 



(2) The winter cycle is much more characteristic of the Maine flocks 

 as a whole than it is of our Rhode Island Reds, where it can be demon- 

 strated in only a portion of the flock. 



(3) The period of decreased flock egg production for Barred Plymouth 

 Rocks and White Wyandottes comes in February. For Rhode Island 

 Reds it may come in January as well as in February. 



(4) A pause, or series of pauses, usually exceeding 10 days in length 

 and following a considerable period of regular egg production, is the best 

 index of the existence of a winter cycle in the individual Rhode Island 

 Red. 



(5) The rate of production does not furnish a satisfactory index of the 

 presence or absence of a winter cycle. 



(6) Evidence is presented which indicates that the winter cycle may 

 be inherited in some definite but undetermined manner. 



LITERATURE CITED 

 (i) Ball, E. D., Alder, Byron, and Egbert, A. D. 



1916. BREEDING FOR EGG PRODUCTION. PART I. A STUDY OP ANNUAL AND 



TOTAL PRODUCTION. Utah Agr. Exp. Sta. Bui. 148, 60 p., 10 fig. 

 Bibliography, p. 59-60. 

 (2) 



1917. BREEDING FOR EGG PRODUCTION. PART II. SEASONAL DISTRIBUTION OF 



EGG PRODUCTION WITH SPECIAL REFERENCE TO " WINTER" EGG PRO- 

 DUCTION. Utah Agr. Exp. Sta. Bui. 149, 71 p., 28 fig. Bibliography, 



P- 55-56- 



(3) Gowell. G. M. 



1902. BREEDING FOR EGG PRODUCTION. In Maine Agr. Exp. Sta. Bui. 79, p. 



26-40. 



(4) 



1903. BREEDING FOR EGG PRODUCTION. In Alainc Agr. Exp. Sta. Bui. 93, p. 



69-76. 



(5) Pearl, Raymond. 



I912. THE mode of INHERITANCE OF FECUNDITY IN THE DOMESTIC FOWL. In 



Jour. Exp. Zool., V. 13, no. 2, p. 153-268, 2 fig. Literature cited, p. 

 266-268. Also published as Maine Agr. Exp. Sta. Bui. 205, p. 283-394. 

 1912. 



(6) 



I915. MEASUREMENT OF THE WINTER CYCLE IN THE EGG PRODUCTION OF 



DOMESTIC FOWL. In Jour. Agr. Research, v. 5, no. 10, p. 429-437. 

 Literature cited, p. 436-437. 



(7) and Surface, F. M. 



I911. A BIOMETRICAL STUDY OF EGG PRODUCTION IN THE DOMESTIC FOWL. 

 II. SEASON.'^L DISTRIBUTION OF EGG PRODUCTION. U. S. Dept. Agt. 



Bur. Anim. Indus. Bui. no, p. 81-120, 30 fig. 



