lOO                       Experim^ental Zoology

314 young, all pigmented; and these last give in later generations
some albinos. The results agree fairly closely with Mendelian
expectations.

Castle has found, as had Allen and Cuenot for mice, that
albinos, although breeding true, may carry latent or suppressed
 

Fig. 7.    Upper figure, short-haired, smooth coat red guinea pig.   Lower figure,
long-haired, rough coat albino.    (After Castle.)

colored characters. Thus one albino individual, a male, when
mated with red females produced offspring marked with black.
Another albino crossed with the same and with other red females
gave young marked with black and red in about half the cases,
the other half showing only red or yellow, but no black. A third
albino mated with red females produces only red or yellow
offspring, never black ones.    In the light of these results, Castle