6 LABORATORY MOUSE 



several color varieties have maintained themselves distinct 

 for many years. For example, a white-bellied colony of mice 

 has been found near Woods Hole, Massachusetts (13Jf.) ; in 

 a region in northern France the black (non-agouti) form has 

 become the sole house mouse to the exclusion of the normal 

 gray variety; the Isle of Wight off the coast of England is 

 populated with the pink-eyed variation. 



The present universal supremacy of M. musculus or 

 M. bactrianus as house mouse is challenged only in very 

 circumscribed localities where the white-footed field mouse 

 occasionally supplants it. The largest such area is thought 

 to be southern Persia, where Apodemus sylvaticus takes its 

 place. 



