=r 
MURIDZE 
(s) Upper incisors not notched ; #! about 
equal in length to m? and wm to- 
gether :— 
(a’) Size smaller; “‘mice” with condylo-| 
basal length rarely exceeding ;-APODEMUS. 
28 mm. : c | 
(a) Skull comparatively massive | eae 
and angular : _j 4. flavicoliis. 
(b) Skull comparatively light and smooth :— 
(a’) Size smaller (condylo-basal) eee 
length not exceeding 24 mm.) J A. syloaticus. 
(b’) Size larger (condylo-basal length 
not less than 24 mm.) :— 
(a) Skull slender; coronoid 
: A. fridariensi. 
process of mandible =| fridariensis 
duced Island). 
(2) Skull normal; coronoid pro- 
cess of mandible not re- 
duced :— 
(a’) Size smaller (condylo-\ 4. ebridensis 
basal length 24-25 mm. J Hebrides). 
(f') Size larger (condylo-basal) 
length 25°5-27 mm.) 
(B') Size larger; “rats” with cones 
basal length rarely less than ;-#P/A/7YS. 
38 mm. . . : | 
(a) Size smaller (condylo- basal 
length rarely reaching 45 mm.); 
cranium broader(external length 
of a parietal distinctly less than 
breadth of cranium between ;£. rattus.* 
lateral ridges); mm! without 
anterior cingulum, with dis- 
tinct outer tubercle to first 
lamina 
(b) Size larger (condylo-basal length 
rarely less than 45 mm.); cra- 
nium narrower (external length 
of a parietal about equal to 
breadth of cranium between 
lateral ridges); m! with an- 
terior cingulum, without outer 
tubercle to first lamina 
EL. norvegicus. 
381 
(Fair 
(Outer 
: jt hirtensts (St Kilda). 
* The sub-species of Zfimys rattus are omitted, as they do not possess diagnostic cranial or 
dental characters. 
VOL. II. 2B2 
