2 THE ZOOLOGIST. 



but with them the belly was quite smooth, though they had the 

 fold of skin on the sides. The eyes were about the ordinary 

 size, and the wrinkles had not developed enough to obscure 

 their vision. In colour they were a dull white, with black eyes 

 and dark ears and tail. They were to all appearance perfectly 

 healthy, and, until they became blind, were as active as ordinary 

 Mice. Two of the males died shortly after I had them, and the 

 female, though she lived for some months, never bred. 



After running the old male with two albino females I obtained 

 a litter from each — one litter consisting of three, and the other 

 of a single young one. These four Mice — a male and three 

 females, the progeny of hairless and albino — were exactly like 

 normal wild Mice in every respect. The male only had a small 

 white spot on the face and belly. He was particularly large and 

 healthy, and lived to be nearly two years old. 



The result of crossing these wild coloured Mice, inter se, and 

 their offspring again, produced normal wild, black, white, black 

 and white, wild and white, and twenty- seven of this " corrugated 

 hairless " type. These hairless were all for the first fortnight of 

 their existence exactly like normal Mice, i. e. born blind and 

 naked ; then the hair grew, and the eyes opened — and, in fact, 

 it was impossible from a litter of that age to pick out the in- 

 dividuals which would eventually develop these corrugations in 

 the skin. 



When from three to five weeks old — for some took longer 

 than others — they began gradually to lose their hair. The 

 nakedness begins about the eyes and on the belly, then shows 

 on the back and head, and gradually spreads over the body 

 until they are perfectly nude, which usually occurs when they 

 are between two and three months old. These corrugations are 

 quite visible on the skin as soon as the nakedness appears, and 

 gradually, as the animal grows older, the skin-folds and wrinkles 

 become thicker, until the eyes are completely closed by the thick 

 skin above them. In colour, twenty-two out of the twenty- seven 

 corrugated which I bred were the usual wild shade before they 

 became hairless, four were black then hairless, and one was a 

 pure albino, with pink eyes and white ears and tail. 



With reference to the article by Gaskoin in the Proc. Zool. 

 Soc. 1856, p. 38, plate — from which I have taken the name Mus 



