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THE AMERICAN NATURALIST [Vol. XLVIII 



to analyze them here. Examples of this type are seen in 

 the zebra, the spotted skunks (Spilogale), the striped 

 weasel (Ictonyx). Probably more than one factor is 

 responsible for some of the combinations of stripes and 

 spots seen, for example, in certain spermophiles (Citelhis 

 13-lineatus), but I shall not now attempt a discussion of 

 these. 



One of the most frequent manifestations of pigment 

 reduction in mammals is the presence of a white spot in 

 the normally pigmented forehead. This is due primarily 

 to the reduction of the ear patches, which fail to meet at 

 their median edges. Perhaps, too, the apparent loss of 

 the crown patch in some mammals still further tends to 

 lessen the amount of pigment production at this point. 

 Babbits and hares very often have more or less white in 

 the forehead, but none of the species has developed this 

 sufficiently to make it a permanent mark. Moseley in his 

 1 'Naturalist on the Challenger/' speaks of a "black 

 variety" of wild rabbit— doubtless introduced— "with a 

 white spot on the forehead" as occasionally found on 

 TenerifTe, Canary Islands, but this mark is common, 

 and I have seen it in such widely sundered species as the 

 eastern varying hare of New Hampshire and the black- 

 necked hare native to Java. A specimen of Leisler's bat 

 {Nyctalus leisleri) in the Museum of Comparative Zool- 

 ogy has a white spot in the middle of the forehead and 

 another on the mid-ventral line of the abdomen — the first 

 a primary break between the ear centers, the second 

 probably a ventral primary break between those of the 

 sides. Among the Insectivora, the West Indian Solen- 

 odon paradoxus has a white patch at the nape of the 

 neck which has become a permanent part of its pattern. 

 It is clearly the enlargement of a primary break sepa- 

 rating the ear patches and neck patches on the median 

 dorsal line. It is a fact of much interest that in a con- 

 siderable scries of this species in the collection of the 

 Museum of Comparative Zoology hardly two have it 

 developed alike, but it varies from a few white hairs to 



