R. C. PUNNETT 231 



result of such a mating. It is hoped to make this experiment in the 

 course of the present year'. 



The results of the matings among the F., agouti-blacks are shewn 

 in Table VI, from which it appears that the results obtained from this 

 series of matings are in fair accordance with the theoretical expectation. 



TABLE VI. 



Male B 144 Male C 32 .Male D 122 Male D 128 



No. of Ag.- Ag.- Ag.- Ag.- 



Female Blk, Blk. Ag. ?= Blk. Blk. Ag. ?2 Blk. Blk. Ag. ?2 Blk. Blk. Ag. ?2 



B76 9 7 3 — — — — — — — — — — — — — 



jBI.51 8 !______ 2 2 2 — — — — — 



B\m 5 1 1 3 585 2 — — — — — — — — 



cm — — — — 3414 — — — — — — — — 



C20 — - — — 641— — — — — 4 3 3 — 



i) 21— — — — 4323 — — — — 5 5 1 4 



D145 — — — — 1372- — — — — — — — — 



Dlo6— — — _ 443— — — — — — — — — 



iil91____ 421— — — — — 4 2 1 — 



J3 237— — — — .5 55— — — — — 6 1 3 1 



£35— — — _ 5 63— — ^ — — 4 2 2 1 



22 9 4 3 49 43 23 9 2 2 2 — 23 13 10 6 



Black Agouti-Black ? - Agouti 



Totals . ■ ... 96 67 18 39 



11 7 



Amended totals ... 107 74 — 39 



Expectation ... 96-25 82 S 41 ■25 



In order to test the agouti-blacks further with respect to the factor 

 E both does and bucks were crossed with Fo heterozygous yellows, and 

 the does also with pure tortoise. Since the gametes of the agouti-black 

 are DEA, DEa, dEA, dEa, and those of the F. yellow deA, dea, the 

 expected result of such a cross is given in Fig. 3. 



The expectation is blacks and agoutis only in the ratio 5 : 3. Tables 

 VII and VIII shew that only blacks and agoutis resulted from such 

 a cross, the actual numbers being 09 black and 33 agouti where the 

 expectation was 64 black and 38 agouti. 



' Since the above was written an F^ black ? made in this way has been shewn to 

 be of the constitution DDEEAa. Crossed with a buck of the constitution ddHEaa she 

 has given only blacks and agouti-blacks. Among the 14 young so bred from her there was 

 no agouti. 



- The rabbits placed in this category were blacks which died too early to determine 

 whether they were true blacks or agouti-black.s. In making the amended total they have 

 been distributed pro rata among these two classes. 



