Common Rat. 173 



the nostrils; the presence on the snout, as also over the eyes, 

 of long tactile bristles, which, like the large eyes and ears, are 

 correlated with the nocturnal habits of the creature ; the presence 

 of a nail on the rudimentary thumb, which is occasionally over- 

 looked or lost in adult specimens; the coarseness of many of the 

 hairs along the middle line of the back ; and the annular arrange- 

 ment of the scales on the tail, and the outgrowth of hair in the 

 intervals of the rings thus formed. 



For an account of the ' hibernating glands,-* see Hirzel and Frey, 

 Zeitschriffc fiir Wissenschaffcliche Zoologie, xii., 3, 165, 1862; 

 Eeker, Wagner's Handworterbuch der Physiologic, iv., p. 121, 

 1853, ibique citata. 



