BLACK-EYED white varieties of rodents have long been. recognized and used as material for genetic investigation. Cuenot, Morgan and Durham with mice and Castle with guinea-pigs have utilized this particular color variety in breeding experiments. For the most part they a-re agreed that black-eyed white varieties represent an extreme condition of the ordinary" spotted" or" piebald" series. Cuenot (1904) in treating the inheritance of spotting concludes that there exists a continuous series of partially pigmented forms extending on the one hand from mice with white on the tail, or with a small white ventral patch, or with small white forehead spot, through a series of decreasingly pigmented forms until the black-eyed white form is reached at the other end of the series. As to a factorial explanation for the phenomena observed in the inheritance of spotting, Cuenot feels that there are numerous stages of the spotted condition (P) which he designates by p, p2, p3, p4 as progressively whiter forms are considered. He believes, however, that the details of spotting are not represented in the germ cell. He further mentions the failure to obtain any particular stage of spotting in a true breeding condition. Selection of nearly solid-colored forms has enabled him to obtain animals with greatly increased white areas. Durham (1908) has obtained some evidence for two different types of spotting, one recessive to solid-coated forms and one dominant to them. She has reported several crosses which I have considered in more or less detail in another paper (Little, 1914). None of the crosses presented by her can be considered as critical tests of the. presence of two distinct spotting factors. Morgan (1909), 727