APODEMUS 503 
and unwieldy genus J7Zus is a constant object of systematists. 
Most recent arrangements seem to have originated with 
Hensel, who in 1856 (Zeztschr. deutsch. geol. Gesellsch., viii., 
289) formed two groups, one containing xorvvegzcus, rattus, and 
musculus, the other sy/vaticus, agrarius, and minutus. Hensel’s 
work, although much neglected or overlooked, was supported 
by Forsyth Major in 1884 (Adz Soc. Tosc. Proc. Vero., iv., 
129) and Thomas in 1905, the latter using A/zcromys to include 
sylvaticus, speciosus, minutus, mystacinus, agrarius, hartt, and 
getsha. \n 1908 Thomas substituted the earlier Apodemus for 
Micromys, and in 1912 Miller restricted the name to agrarzus, 
sylvaticus, epimelas, and their allies, the genus Azcromys being 
restricted to the Harvest Mouse (A/us minutus of Pallas) and 
its allies. 
Characters:—The mice of this genus are rather generalised, 
and not markedly modified by specialisation in any particular 
direction. Their ears have no special meatal valves : their 
tail is not prehensile. They have six or eight mamma, of 
which two pairs are inguinal, and one or two pairs pectoral. 
Their skull has the rostrum well developed, so that, unlike 
that of Mecromys, the diastema is distinctly longer than the 
cranial depth at the anterior root of m'; the palatal shelf is 
squarely or roundly notched behind by the posterior nares, 
though sometimes provided with a short central spinous 
process ; #' and m” are complex, having three cusps on their 
inner sides (Pl. XXVIII., Figs. 4-6, 2’, 6, 7). 
The genus is widely distributed in arctic, boreal, and 
transitional regions of the Old World, from Ireland to Japan, 
and from northern Skandinavia and corresponding latitudes 
to the Barbary States of North Africa, Palestine, Persia, and 
northern India. It is absent from Kamtschatka. It is first 
known from the late Pliocene (Forest Bed) of England, and is 
evidently of Old World origin. 
The complexity of the cheek-teeth is a primitive character 
which assigns to Afodemus the lowest status among European 
Murine. The combination of such cheek-teeth, non-prehen- 
sile tail, and normal skull is quite distinctive amongst Palearctic 
genera, and is not exhibited by any Oriental or Australian 
species. Some African mice (7amnomys, Thomas, Ann. and 
