502 MURIDA!-—APODEMUS 
teeth above and below, and therefore throughout the sub- 
family (as in other JZurzde) mo are the largest and most 
. . 2 
complex or conservative teeth of the series ; m— are much 
smaller, and certain of the cusps, present in the forward part 
of my, are not developed; because of their posterior position 
and consequent slight mechanical importance ms 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, ¢.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 Ep~zmys and AZus have, as parasites upon humanity, 
acquired a secondary distribution of world-wide exent. 
Murine 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, 1. 150 and 154 ; 
based on Mus agrartus of Pallas, Move Species Quad. e Glirium, 1779, 95, 
described from Berlin, Germany; Thomas, Az. and Mag. Nat. Hist., May 
1908, 447 (part) ; Miller, Ca¢alogue. 
1905. Micromys, Oldfield Thomas, Av. 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 
1 Some exotic Murine, 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. 
GC — ——————— 
ee 
enigpeaiiptinisalea, 
