COAT CHARACTERS IN GUINEA-PIGS AND RABBITS. 



with dark eyes. Time will show whether this is possible. It is not 

 improbable that practical difficulties may be encountered. Experi- 

 enced breeders say that the " purest" albino guinea-pigs (/. e., those 

 most free from peripheral pigmentation) incline to sterility. Two 

 cases which have occurred in my own experiments make me think 

 there is some truth in this idea. Further, albinos free from latent 

 black have not yet been mated inter se, but I shall not be surprised 



TABLE H. Matings of males mentioned in Table G -aiith animals black pig- 

 mented, but having albinism recessive. The expected proportion of albinos 

 is i in 4. 



TABLE I. Matings of males mentioned in Table G -with albino females, 

 expected that half the offspring -will be albinos. 



It is 



to find them relatively unproductive when this is done, for the hybrids 

 bred inter se have in certain cases produced fewer albino young than 

 they should produce on the Mendelian hypothesis. Thus, an exami- 

 nation of Table G shows that only 8 albinos have been produced in a 

 total of 54 young, where 13.5 are expected. Nevertheless, this may 

 be only a chance deviation from the expected proportion of albinos 

 which will disappear as larger numbers are produced. Tables H and 

 I indicate that the hybrid males employed in the matings enumerated 



