COAT CHARACTERS IN GUINEA-PIGS AND RABBITS. 69 



other than inter se, which should give some indication of whether any 

 correlations exist among the three pairs of coat-characters. Thus 

 triple hybrids were mated with several pure pigmented, smooth, and 

 short-haired individuals, P. Sm. Sh., as follows: 



All the young were, as expected, pigmented and short-haired. It is 

 expected, further, that half will be rough, half smooth, and this result 

 is approximated in the observed 15 rough to 13 smooth. The young, 

 though visibly of only two sorts, should be on the hypothesis that no 

 correlations exist among the pairs of coat-characters of eight different 

 sorts, all equally numerous. For the gametes of the triple hybrids 

 should be as follows : P. R. Sh. + P. R. L. + P. Sm. St. + P. Sm. 

 L. + A. R. Sh. + A. R. L. + A. Sm. Sh. + A. Sm. L. But the 

 gametes of the pure mates used should all be P. Sm. Sh., and the 

 zygotes formed (i. e., the characters present in the young) should be 

 with equal frequency of these eight sorts, parentheses indicating reces- 

 sives not visible : 



5. P.(A.)R. (Sm.) SA. 



6. P. (A.) R. (Sm.) SA. (L.) 



7. P. (A.) Sm. SA. 



8. P. 04.) Sm. SA. (L.) 



1. P. R. (Sm.) SA. 



2. P. R. (Sm.) SA. (L.) 



3. P. Sm. SA. 



4. P. Sm. SA. (L.) 



The tests to determine what recessives each of the young possesses 

 are not yet complete, but thus far show the following distribution : 



Class i. i (or 2) individuals. Class 5. i individual. 



Class 2. i (or 2) individuals. Class 6. 2 (or 3) individuals. 



Class 3. i individual. Class 7. None. 



Class 4. None. Class 8. 4 individuals. 



Considering that only ten individuals have as yet been fully tested, 

 their distribution among the classes is sufficiently wide to indicate the 

 probable absence of correlation among the three pairs of coat-characters. 

 The full details of the several tests on which this classification of indi- 

 viduals is based will be given in a subsequent report when a larger 

 number of tests has been completed. 



