1908.] Transmission of certain Coat Characters in Rats. 393 
Summary. 
These experiments show that albinoes breed true to albinism, whether 
their ancestry is pigmented or not. They further show that, though 
externally albinoes may appear to be identical with regard to their coat 
characters, in reality they may be different. This fact has been previously 
known for both animals and plants, but it has hitherto been elucidated by 
means of breeding tests alone. These experiments add an ocular demon- 
stration of the actual presence of the coat-pattern in albinoes.. The 
interpretation placed upon the coat appearances in these albinoes is 
corroborated by the breeding results. 
It is further shown that when a piebald black rat (Cr 5) is mated with a 
similar one, two classes of offspring may be obtained. One of these contains 
all black piebalds and the other a mixture of black piebalds and albinoes 
in nearly equal numbers. 
When a piebald black rat is mated with an albino (=Cr. 5 x Cr 4), it may 
be said that, so far as these experiments have gone, five different results will 
be obtained. They may be stated as follows: (1) The offspring are all black 
piebalds. (2) They may be a mixture of black piebalds and albinoes. 
(3) They may be all “ Irish” forms (=a black self-coloured form). (4) They 
may be a mixture of albinoes, black piebalds, and “Irish.” (5) They may 
contain albinoes, “ Irish,” and a grey form (=Cr 2). It can be shown that 
the divergency of the results obtained when two individuals apparently 
similar are mated is due to the gametic nature of the albino employed. 
