R. C. PUNNETT 225 



produced by a tortoise and one produced by a heterozygous yellow. 

 Aod with a single exception, which will subsequently be dealt with 

 more fully, the breeding results indicate that all the blacks are similar. 

 These results are set out in Table II which shews not only the 

 matings between the F^ animals but also the effect of crossing them 

 with pure tortoise ((/" 74) and pure Himalayan ((/■ 116). All the 

 results accord closely with expectation. 



Agouti from Black x Black. 



So far the experiments had merely served to confirm the work of 

 previous writers and offered nothing of novelty beyond the fact that 

 the black of the Himalayan rabbit can behave like the black of the 

 ordinary self-coloured. All the Fj blacks hitherto dealt with were the 

 progeny of a yellow or a tortoise doe by a Himalayan buck (J' 7) and 

 with two exceptions all the F, animals used were made in this way. 

 The two exceptions were an agouti ( J 27) and a black (f/" 28) reared 

 from the mating of the Himalayan doe ( ^ 7) with the yellow buck 

 ((/" 5). The agouti doe behaved like the other ^i agoutis and her 

 progeny have been included in Table I. (f 28 however proved to be 

 a remarkably interesting rabbit. He was a pure self-coloured black 

 to look at, and, unlike most of the Fi animals, shewed no touch of 

 white marking in spite of a Dutch parent. For this reason I reserved 

 him out of a number of F^ bucks for the breeding of the F^ generation. 

 The mating of this animal with the F^ black does led to a striking and 

 entirely unlooked for result, for from this mating of black x black came 

 not only the expected blacks and tortoises but also yelloius and agoutis^. 

 Further, among the blacks certain individuals were characterised by 

 the development of some agouti hairs, a feature which was especially 

 well marked in the area between the nape of the neck and the shoulder 

 blades (cf PI. XII, fig. 2). The amount of agouti hairs was somewhat 

 variable and on the whole they were rather more abundant in the males 

 than in the females. Generally speaking these hairs only became 

 conspicuous about the third week after birth and rantil then it is not 

 possible to distinguish with certainty between these " black-agoutis " 

 and true blacks. Both also are black bellied. 



' Woods (8) also obtained some agoutis from the mating of black with black. His 

 experiments were made in pre-Mendelian days and the data are insufficient for analysis. 

 But as yellows and apparently also tortoises appeared in his litters it is quite likely that 

 the hypothesis given later would serve to explain his results also if we knew more about 

 them. 



