INHERITANCE OF FECUNDITY 247 



It will be noted that the one 'Over 30' bird laid but 41 eggs. 

 The record probably represents a fluctuation from the ' Under 30' 

 class. In general the agreement between observation and expec- 

 tation is satisfactory. 



Turning to the matings of o^ 578 with barred Fi females we 

 meet the only case in the whole investigation which is apparently 

 unconformable. It will therefore be well to discuss it in detail. 

 The facts are these : a" 578 was mated with four barred Fi females, 

 of which three were in the 'Over 30' class and one was a poor layer. 

 When mated with any of these the high laying birds one half of 

 578's daughters should have been in the 'Over 30' and one-half 

 in the 'Under 30' class. Mated with the poor layer only zero 

 birds should have resulted. Nothing like this actually happened. 

 The observed outcome was that shown in the following table: 



Mating 699 (d^578 X 9-111) gave 13 adult daughters, with winter records as 

 follows : 62, 60, 56, 32, | 30, | 28, 27, 26, 26, 7, 5, 5, 2. 



Mating 700 (cf 578 X 9 422) gave 7 adult daughters with winter records as fol- 

 lows: 47, 47, 33, I 26, 19, 15, 9. 



Mating 701 (cf 578 X 9 414) gave 5 adult daughters with winters records as 

 follows: I 23, 16, 5,0, 0. 



Mating 702 (cf 578 X 9 423) gave 11 adult daughters with winter records as 

 follows: 40, 34, | 28, 26, 21, 20, 17, 15, 13, 10, 4. 



These records are characterized by four striking facts: (a) the 

 large number of ' Over 30 ' records when none is expected, (6) 

 the large number of high 'Under 30' records, (c) the absence 

 except in one mating of zero records, and {d) the sharp break 

 within the 'Under 30' class, especially to be noted in mating 699, 

 but also clear in each of the others. 



Now these four matings were remarkable in other respects 

 than the egg records of the progeny. They gave an extraordi- 

 narily high hatching record. This is shown in table 32. 



Considering that these figures include all eggs set during the 

 whole hatching season it is evident that the record is relatively 

 very high. In a former paper (30) I have shown (loc. cit., table 

 B, p. 131) that for the high laying Barred Rock matings the mean 

 percentage of fertile eggs was 80.7 per cent., while 55.1 per cent 

 of the fertile eggs were hatched. Even those results could only be 



