114 PROCEEDINGS OF THE AMERICAN ACADEMY. 



(3) The pleural patches are separated ventrally, leaving a narrow white 

 belly streak. (4) The pleural aud the sacral patches have not fully 

 coalesced on the dorsal part of the rump, leaving thus a median white 

 spot, and the restriction of the sacral patches has given a white tail and 

 white hind feet. Various degrees of increased restriction of i)igmeut 

 toward the diflfereut centres are possible, and the ultimate extreme condi- 

 tion is the complete absence of pigment about a centre. Thus, Figure 5 

 shows the condition obtaining in the writer's black-white male 303. The 

 genal aud nuchal pigment patches are practically intact, though a break 

 in the middle of the forehead and a white streak along the throat show 

 that the two former are suffering restriction. A white collar nearly sep- 

 arates the nuchal from the scapular patches, aud the latter have shrunk 

 away, as it were, from the belly and fore limbs, while posteriorly a notch 

 in the median dorsal line indicates that a further restriction would divide 

 the color area into right and left patches. One of the pleural patches, 

 that on the left side, has disappeared altogether ; the other is entirely 

 free from the scapular patch, and nearly so with respect to the sacral 

 25atch of its own side. It will be observed that the single pleural patch 

 tends to encroach very slightly on the area which its fellow normally 

 would cover. The two sacral patches are fairly distinct, the one on the 

 right being more extensive. The two fuse posteriorly and include 

 the root only of the tail. Figure 6 represents a still more extreme 

 case of restricted pigmentation ; it is the color pattern of a black-white 

 Japanese dancing mouse obtained from a dealer. The genal patches are 

 reduced so as to leave a wide white blaze on the forehead, and the 

 shoulder patches, too, are very much reduced, though they have not 

 broken from the neck patches. The sacral patches are represented by 

 two very small centres, one on either side of the base of the tail. The 

 pleural patches have disappeared entirely. The writer has seen similar 

 mice in which the shoulder patches also were gone. Hence it is not 

 difficult mentally to picture a mouse in which all the patches have be- 

 come eliminated, by selection or otlierwise, giving a pure white individ- 

 ual with black eyes as the condition of partial albinism whose opposite 

 extreme is an animal totally pigmented except at the tip of the tail. The 

 actual occurrence of a white mouse with black eyes has been established 

 by Bateson (: 03'', p. 74), who states that to his knowledge '• strains of 

 this type have been independently produced twice." Among other ani- 

 mals also individuals of this sort are known. Thus among horses, cattle, 

 dogs, cats, guinea pigs, hens, and even doves, white individuals with pig- 

 mented eyes are not uncommon. It seems difficult to obtain such a race 



