502 MURID^— APODEMUS 



teeth above and below, and therefore throughout the sub- 

 family (as in other Muridce) m- are the largest and most 



complex or conservative teeth of the series ; m- are much 



smaller, and certain of the cusps, present in the forward part 

 of OTi, are not developed ; because of their posterior position 

 and consequent slight mechanical importance m^ are greatly 



reduced both in size and in the number of their constituent 

 tubercles, and in several murines these teeth are even entirely 

 suppressed. 



The skin of the tail becomes detached very readily in some 

 species, e.g. in Apodemus sylvaticus, being, perhaps, like the 

 brittle tail of dormice (see above, ii., 350), a safeguard against 

 capture by enemies/ A mouse which has "escaped by the 

 skin of its tail " generally eats down the injured appendage 

 until it reaches the point where the skin parted. 



The sub-family contains, according to Miller, about fifty 

 described genera, four of which occur in Britain. Its members 

 are distributed naturally throughout the Old World, with the 

 exception of Madagascar and New Zealand ; species of the 

 genera Epimys and Mus have, as parasites upon humanity, 

 acquired a secondary distribution of world-wide exent. 



Murince are first known from the Upper Miocene of 

 Europe, and the Pliocene of India ; they must have originated 

 in the Old World somewhere to the south of the temperate 

 regions, reaching the latter too late to find their way to 

 North America. 



Genus APODEMUS. 



1829. Apodemus, Jakob Kaup, System der Europaischen Thierwelt, i., 150 and 154; 

 based on Mus agrarius of Pallas, Novce Species Quad, e Glirium, 17T), 95, 

 described from Berlin, Germany ; Thomas, Ann. and Mag. Nat. Hist., May 

 1908, 447 (part) ; Miller, Catalogue. 



1905. MiCROMYS, Oldfield Thomas, Ann. and Mag. Nat. Hist., May 1905, 492 (part). 



Mus of most writers prior to Thomas, 1905, quoted above. 



Synonymy and classification: — The subdivision of the large 



' Some exotic Murina, e.g. Acomys (see Bate, Ann. and Mag. Nat. Hist, June 

 1903, 566), have also very brittle tails, but this does not seem to be the case with 

 any British species. 



