POULTRY NOTES — 1909. 95 



3. Turning now to the consideration of the hatching quality 

 of the eggs in the two different crosses, it appears to be the 

 case in the present statistics that the fertile eggs of either 

 Barred Plymouth Rock or Cornish Indian Game females are 

 more likely to hatch if they are fertilized with spermatozoa of 

 the other breed than if they are fertilized with their own sperma- 

 tozoa. That is to say, in these experiments the percentage of 

 fertile eggs hatched was higher for the cross fertilized eggs 

 than for either of the pure breeds under the same environmental 

 conditions, regardless of the direction of the cross. The data 

 in the case are as follows : For the Barred Plymouth Rock 

 pullets in the whole breeding season of 1909, the average per- 

 centage of fertile eggs hatched was 47.67 ± 1.80.* The pure 

 matings of Cornish Indian Games in the same season gave an 

 average of 55 percent of fertile eggs hatched, as shown in 

 Table 6. For the hybrids, as shown in Tables 4 and 5, the 

 average figures of the whole season are 73 percent of fer- 

 tile eggs hatched for the cross in one direction (Barred Ply- 

 mouth Rock (^ X Cornish Indian Game $) and 66 percent of 

 fertile eggs hatched in the reciprocal cross. In other words, 

 the hybrid germ cell (fertilized ovum) appears to possess 

 greater developmental vigor than does the pure germ cell. This 

 is shown not only in the greater viability of the eggs during 

 incubation, but also in other ways. These hatching records, 

 however, furnish a novel kind of evidence of the well known 

 phenomenon of greater vigor in hybrids. 



4. The "percentage of fertile eggs dying in the shell" is 

 obviously the arithmetic complement of the "percentage of fer- 

 tile eggs hatched" and does not need particular discussion. 



We may turn next to a consideration of the mortality and 

 sex ratio records. The data for all hybrid chickens hatched in 

 the whole season are given in Table 7, while the data for all 

 chickens hatched in the season for pure matings are in Table 8. 

 In order to save space detailed data for each individual mating 

 are not given in the case of the pure bred chicks. 



*Cf. Me. Agr. Exp. Sta. Bulletin 168. Table VI, p. 119. 



