64 INHERITANCE IN RABBITS 



young; expected i: i. We have had several other yellow rabbits which 

 were probably of this same variety, but they were less extensively and 

 inconclusively tested. 



Variety 2 is represented in a yellow rabbit obtained by purchase 

 (<?i256). He was mated with 9547 yellow, variety 3, and produced 

 9 young, all yellow (as expected) ; by yellow 9 745?, variety 4, he produced 

 4 yellow and 3 white young (expected 3:1); and by black 9 1230 and 

 9 1231, variety 7, he produced 8 yellow, 3 gray, and i blue-gray young; 

 expected 4:3: i. 



Variety 3 is represented in yellow females 547, 714, and 1115, which 

 in matings with yellow males of variety 4 produced 24 yellow and 2 sooty 

 young, but no white ones. Had these females been of variety 4 they 

 should have produced 25 per cent of white young in the mating mentioned. 

 It is possible that the recorded number of sooties is too small, owing to 

 a failure in our earlier records to discriminate sooty from yellow. No 

 such possibility exists in the case of the records for albinos. One of the 

 females already mentioned, of variety 3 (9 1115), when mated with sooty 



3 1340 produced 2 yellow and 6 sooty young. 



Another yellow rabbit of variety 3 was the lop c?i79 (plate 2, fig. 8). 

 When mated with the sooty "old female lop" (plate i, fig. 2) he produced 



4 yellow and 4 sooty young (expected i : i) ; and when mated with black 

 females of variety 4 (9 9 105, 167, and 247) he produced 7 gray, 5 black, 



6 yellow, and 7 sooty young (expected i: i: i: i). Notice in the matings 

 with black females the total absence of albinos, though all these females 

 had produced albinos by other mates. 



Still another male of variety 3, ^319, son of the sooty old female lop 

 by gray c? 176, variety 5, when mated with the black 9 247 (variety 4) 

 produced 2 gray, 2 black, 2 yellow, and i sooty young (expected i : i : i : i). 



Variety 4 is represented in our "Cutler's yellow" and in 9 745^ pro- 

 duced by black 9105 (variety 4) mated with yellow ^319 (variety 3). 

 When "Cutler's yellow" was mated with the above female, 745^-, he pro- 

 duced 4 yellow, 3 sooty, and i white young (expected 9:3:4). When 

 mated with sooty females 632 and 647 (variety 2), he produced 7 yellow, 



7 sooty, and 2 white young (expected 3:3:2). 



SOOTY. 



Sooty rabbits differ from yellow ones only in the factor A, which they 

 lack. Theoretically 8 varieties are possible, viz: 



(1) Sooties producing sooties only, when mated inter se; formula, B 2 Br 2 R 2 C 2 I 2 U 2 Y 2 . 



(2) Sooties producing sooty, and white; formula, B 2 Br 2 R 2 CI 2 U 2 Y 2 . 



(3) Sooties producing sooty, and pale sooty; formula, B 2 Br 2 R 2 C 2 I(D)U 2 Y 2 . 



(4) Sooties producing sooty, pale sooty, and white; formula, B,Br 2 R 2 CI(D)U 2 Y 2 . 



The 4 remaining varieties would be like these, except as regards the 

 factor U, in which they would be heterozygous, U(S), instead of homozy- 



